feat: external databases — register, probe, encrypted credentials

Databases hosted outside Containr can now be registered alongside
managed ones. The connection is probed before storing (protocol-level
for postgres/redis-family via real drivers, TCP dial for the rest),
credentials are encrypted at rest and never returned, and external rows
skip managed lifecycle actions, backups, and Docker metrics.

- POST /databases/register-external — probe + create
- POST /databases/test-connection — ad-hoc probe (ok/latency_ms/error)
- POST /databases/{id}/test-connection — re-probe stored credentials
- provider/external fields on database services; privileged reads get a
  composed connection URL with loopback hosts rewritten to the caller's
- CLI: databases register + test-connection; MCP: 3 new tools
- UI: managed/external toggle in the create modal, external badge and
  host display, per-row test button, backups section hidden
- Migration widens the plan CHECK to admit 'external'

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/backend/internal/api/databases.go

@@ -4,6 +4,7 @@ import (
 	"archive/tar"
 	"containr/internal/database/sqlcdb"
 	"containr/internal/docker"
+	"containr/internal/secrets"
 	"context"
 	"crypto/rand"
 	"database/sql"
@@ -51,12 +52,30 @@ type DatabaseService struct {
 	Region         string               `json:"region" db:"region"`
 	BackupSchedule string               `json:"backup_schedule,omitempty"`
 	NextBackupAt   *time.Time           `json:"next_backup_at,omitempty"`
+	Provider       string               `json:"provider"`           // managed | external
+	External       *DatabaseExternalRef `json:"external,omitempty"` // connection target for external DBs
 	CreatedAt      time.Time            `json:"created_at" db:"created_at"`
 	UpdatedAt      time.Time            `json:"updated_at" db:"updated_at"`
 	ConnectionURL  string               `json:"connection_url"`
 	Metrics        DatabaseMetrics      `json:"metrics"`
 	Backups        DatabaseBackupConfig `json:"backups"`
 	Settings       DatabaseSettings     `json:"settings"`
+
+	// externalPasswordEnc is the stored ciphertext — needed to compose the
+	// connection URL on privileged reads, never serialized.
+	externalPasswordEnc string `json:"-"`
+}
+
+// DatabaseExternalRef describes a registered external database's connection
+// target. The password is stored encrypted and never returned — has_password
+// signals presence.
+type DatabaseExternalRef struct {
+	Host        string `json:"host"`
+	Port        int    `json:"port"`
+	Database    string `json:"database"`
+	Username    string `json:"username"`
+	HasPassword bool   `json:"has_password"`
+	SSL         bool   `json:"ssl"`
 }
 
 // DatabaseMetrics represents database performance metrics
@@ -467,21 +486,20 @@ func (h *DatabaseHandler) DeleteDatabase(c *gin.Context) {
 	databaseID := c.Param("id")
 	userID = h.effectiveUserID(c, userID, databaseID)
 
-	exists, err := h.queries.DatabaseServiceExistsByIDAndUser(c.Request.Context(), sqlcdb.DatabaseServiceExistsByIDAndUserParams{
+	row, err := h.queries.GetDatabaseServiceByIDAndUser(c.Request.Context(), sqlcdb.GetDatabaseServiceByIDAndUserParams{
 		ID:     databaseID,
 		UserID: userID,
 	})
 	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			c.JSON(http.StatusNotFound, gin.H{"error": "Database not found"})
+			return
+		}
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to check database"})
 		return
 	}
 
-	if !exists {
+	if row.Provider != "external" && h.dockerClient != nil {
-		c.JSON(http.StatusNotFound, gin.H{"error": "Database not found"})
-		return
-	}
-
-	if h.dockerClient != nil {
 		if err := h.deleteManagedDatabaseRuntime(databaseID); err != nil {
 			c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to delete runtime database"})
 			return
@@ -515,17 +533,24 @@ func (h *DatabaseHandler) PerformDatabaseAction(c *gin.Context) {
 		return
 	}
 
-	exists, err := h.queries.DatabaseServiceExistsByIDAndUser(c.Request.Context(), sqlcdb.DatabaseServiceExistsByIDAndUserParams{
+	row, err := h.queries.GetDatabaseServiceByIDAndUser(c.Request.Context(), sqlcdb.GetDatabaseServiceByIDAndUserParams{
 		ID:     databaseID,
 		UserID: userID,
 	})
 	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			c.JSON(http.StatusNotFound, gin.H{"error": "Database not found"})
+			return
+		}
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to check database"})
 		return
 	}
 
-	if !exists {
+	if row.Provider == "external" {
-		c.JSON(http.StatusNotFound, gin.H{"error": "Database not found"})
+		c.JSON(http.StatusBadRequest, gin.H{
+			"error": "Lifecycle actions apply to managed databases only — external databases are run elsewhere",
+			"code":  "VALIDATION",
+		})
 		return
 	}
 
@@ -619,6 +644,13 @@ func (h *DatabaseHandler) CreateBackup(c *gin.Context) {
 		c.JSON(http.StatusConflict, gin.H{"error": "Database is still provisioning"})
 		return
 	}
+	if row.Provider == "external" {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"error": "Backups run against the managed dump pipeline — external database backups are not supported yet",
+			"code":  "VALIDATION",
+		})
+		return
+	}
 
 	backupID := generateDatabaseBackupID(databaseID)
 	archivePath := sanitizeBackupArchivePath(managedDatabaseBackupArchivePath(backupID))
@@ -659,17 +691,23 @@ func (h *DatabaseHandler) RestoreBackup(c *gin.Context) {
 		return
 	}
 
-	exists, err := h.queries.DatabaseServiceExistsByIDAndUser(c.Request.Context(), sqlcdb.DatabaseServiceExistsByIDAndUserParams{
+	dbRow, err := h.queries.GetDatabaseServiceByIDAndUser(c.Request.Context(), sqlcdb.GetDatabaseServiceByIDAndUserParams{
 		ID:     databaseID,
 		UserID: userID,
 	})
 	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			c.JSON(http.StatusNotFound, gin.H{"error": "Database not found"})
+			return
+		}
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to check database"})
 		return
 	}
-
+	if dbRow.Provider == "external" {
-	if !exists {
+		c.JSON(http.StatusBadRequest, gin.H{
-		c.JSON(http.StatusNotFound, gin.H{"error": "Database not found"})
+			"error": "Restores run against the managed dump pipeline — external database restores are not supported yet",
+			"code":  "VALIDATION",
+		})
 		return
 	}
 
@@ -787,7 +825,7 @@ func (h *DatabaseHandler) DownloadBackup(c *gin.Context) {
 }
 
 func (h *DatabaseHandler) resolveDatabaseMetrics(ctx context.Context, db DatabaseService) DatabaseMetrics {
-	if h.dockerClient == nil {
+	if h.dockerClient == nil || db.Provider == "external" {
 		return h.generateMockMetrics()
 	}
 
@@ -945,7 +983,11 @@ func (h *DatabaseHandler) generateMockSettings() DatabaseSettings {
 
 // resolveConnectionURL returns the stored connection URL for privileged
 // viewers, or "" when the runtime has not produced one (not provisioned yet).
+// External databases compose it from the registered fields on demand.
 func (h *DatabaseHandler) resolveConnectionURL(db DatabaseService) string {
+	if db.Provider == "external" && db.External != nil {
+		return externalConnectionURL(db.Type, db.External, secrets.Decrypt(db.externalPasswordEnc))
+	}
 	return strings.TrimSpace(db.ConnectionURL)
 }
 
@@ -987,7 +1029,7 @@ func rewriteLoopbackURL(rawURL, host string) string {
 }
 
 func (h *DatabaseHandler) reconcileManagedDatabaseState(ctx context.Context, db DatabaseService) DatabaseService {
-	if h.dockerClient == nil {
+	if h.dockerClient == nil || db.Provider == "external" {
 		return db
 	}
 
@@ -1054,7 +1096,7 @@ func (h *DatabaseHandler) resolveManagedRuntimeStatus(ctx context.Context, db Da
 }
 
 func mapDatabaseServiceRow(row sqlcdb.DatabaseService) DatabaseService {
-	return DatabaseService{
+	svc := DatabaseService{
 		ID:             row.ID,
 		OwnerID:        row.UserID,
 		Name:           row.Name,
@@ -1065,10 +1107,23 @@ func mapDatabaseServiceRow(row sqlcdb.DatabaseService) DatabaseService {
 		Region:         row.Region,
 		BackupSchedule: databaseNullString(row.BackupSchedule),
 		NextBackupAt:   databaseNullTimePtr(row.NextBackupAt),
+		Provider:       row.Provider,
 		ConnectionURL:  databaseNullString(row.ConnectionUrl),
 		CreatedAt:      databaseNullTime(row.CreatedAt),
 		UpdatedAt:      databaseNullTime(row.UpdatedAt),
 	}
+	if svc.Provider == "external" {
+		svc.External = &DatabaseExternalRef{
+			Host:        databaseNullString(row.ExternalHost),
+			Port:        int(row.ExternalPort.Int32),
+			Database:    databaseNullString(row.ExternalName),
+			Username:    databaseNullString(row.ExternalUsername),
+			HasPassword: row.ExternalPassword != "",
+			SSL:         row.ExternalSsl,
+		}
+		svc.externalPasswordEnc = row.ExternalPassword
+	}
+	return svc
 }
 
 func databaseNullTime(value sql.NullTime) time.Time {

app/backend/internal/api/dbexternal.go

@@ -0,0 +1,319 @@
+package api
+
+import (
+	"context"
+	"crypto/tls"
+	"database/sql"
+	"errors"
+	"fmt"
+	"net"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"containr/internal/database/sqlcdb"
+	"containr/internal/secrets"
+
+	"github.com/gin-gonic/gin"
+	"github.com/go-redis/redis/v8"
+)
+
+// externalDatabaseRequest is the shared payload for registering an external
+// database and for ad-hoc connection tests.
+type externalDatabaseRequest struct {
+	Name     string `json:"name"`
+	Type     string `json:"type" binding:"required"`
+	Host     string `json:"host" binding:"required"`
+	Port     int    `json:"port"`
+	Database string `json:"database"`
+	Username string `json:"username"`
+	Password string `json:"password"`
+	SSL      bool   `json:"ssl"`
+}
+
+var externalDefaultPorts = map[string]int{
+	"postgresql": 5432,
+	"mysql":      3306,
+	"mariadb":    3306,
+	"mongodb":    27017,
+	"redis":      6379,
+	"dragonfly":  6379,
+	"clickhouse": 9000,
+}
+
+// externalConnectionURL composes a DSN for display/bind use. The password is
+// embedded only on privileged reads — the value is decrypted at that point.
+func externalConnectionURL(dbType string, ext *DatabaseExternalRef, password string) string {
+	host := net.JoinHostPort(ext.Host, fmt.Sprintf("%d", ext.Port))
+	creds := ""
+	if ext.Username != "" {
+		creds = url.QueryEscape(ext.Username)
+		if password != "" {
+			creds += ":" + url.QueryEscape(password)
+		}
+		creds += "@"
+	}
+	switch dbType {
+	case "postgresql":
+		u := fmt.Sprintf("postgres://%s%s/%s", creds, host, ext.Database)
+		if ext.SSL {
+			u += "?sslmode=require"
+		}
+		return u
+	case "mysql", "mariadb":
+		return fmt.Sprintf("mysql://%s%s/%s", creds, host, ext.Database)
+	case "mongodb":
+		u := fmt.Sprintf("mongodb://%s%s/%s", creds, host, ext.Database)
+		if ext.SSL {
+			u += "?tls=true"
+		}
+		return u
+	case "redis", "dragonfly":
+		scheme := "redis"
+		if ext.SSL {
+			scheme = "rediss"
+		}
+		// Redis auth is password-only; username support is ACL-era.
+		if password != "" {
+			creds = ":" + url.QueryEscape(password) + "@"
+			if ext.Username != "" {
+				creds = url.QueryEscape(ext.Username) + creds
+			}
+		}
+		return fmt.Sprintf("%s://%s%s", scheme, creds, host)
+	case "clickhouse":
+		return fmt.Sprintf("clickhouse://%s%s/%s", creds, host, ext.Database)
+	}
+	return fmt.Sprintf("%s://%s%s", dbType, creds, host)
+}
+
+// probeExternalDatabase verifies reachability. postgres and redis-family get
+// real protocol checks via the vendored drivers; everything else gets a TCP
+// dial — enough to catch typos and firewall issues without new dependencies.
+func probeExternalDatabase(ctx context.Context, req externalDatabaseRequest) (time.Duration, error) {
+	addr := net.JoinHostPort(req.Host, fmt.Sprintf("%d", req.Port))
+	dialer := &net.Dialer{Timeout: 5 * time.Second}
+	start := time.Now()
+
+	switch req.Type {
+	case "postgresql":
+		sslmode := "disable"
+		if req.SSL {
+			sslmode = "require"
+		}
+		dsn := fmt.Sprintf("postgres://%s:%s@%s/%s?sslmode=%s&connect_timeout=5",
+			url.QueryEscape(req.Username), url.QueryEscape(req.Password), addr,
+			url.QueryEscape(req.Database), sslmode)
+		conn, err := sql.Open("postgres", dsn)
+		if err != nil {
+			return 0, err
+		}
+		defer conn.Close()
+		if err := conn.PingContext(ctx); err != nil {
+			return 0, err
+		}
+	case "redis", "dragonfly":
+		client := redis.NewClient(&redis.Options{
+			Addr:        addr,
+			Username:    req.Username,
+			Password:    req.Password,
+			DialTimeout: 5 * time.Second,
+			ReadTimeout: 5 * time.Second,
+			TLSConfig:   redisTLSConfig(req.SSL, req.Host),
+		})
+		defer client.Close()
+		if err := client.Ping(ctx).Err(); err != nil {
+			return 0, err
+		}
+	default:
+		conn, err := dialer.DialContext(ctx, "tcp", addr)
+		if err != nil {
+			return 0, err
+		}
+		conn.Close()
+	}
+	return time.Since(start), nil
+}
+
+func redisTLSConfig(enabled bool, host string) *tls.Config {
+	if !enabled {
+		return nil
+	}
+	return &tls.Config{ServerName: host, MinVersion: tls.VersionTLS12}
+}
+
+// handleTestDatabaseConnection probes arbitrary connection parameters — used
+// by the register form's "test" button and by agents before registering.
+func (h *DatabaseHandler) TestDatabaseConnection(c *gin.Context) {
+	if _, ok := requireAuthenticatedUserID(c); !ok {
+		return
+	}
+	var req externalDatabaseRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error(), "code": "VALIDATION"})
+		return
+	}
+	if err := normalizeExternalRequest(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error(), "code": "VALIDATION"})
+		return
+	}
+
+	ctx, cancel := context.WithTimeout(c.Request.Context(), 10*time.Second)
+	defer cancel()
+	latency, err := probeExternalDatabase(ctx, req)
+	if err != nil {
+		c.JSON(http.StatusOK, gin.H{"ok": false, "error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true, "latency_ms": latency.Milliseconds()})
+}
+
+// TestDatabaseConnectionByID re-probes a registered external database using
+// its stored (decrypted) credentials.
+func (h *DatabaseHandler) TestDatabaseConnectionByID(c *gin.Context) {
+	userID, ok := requireAuthenticatedUserID(c)
+	if !ok {
+		return
+	}
+	databaseID := c.Param("id")
+	userID = h.effectiveUserID(c, userID, databaseID)
+
+	row, err := h.queries.GetDatabaseServiceByIDAndUser(c.Request.Context(), sqlcdb.GetDatabaseServiceByIDAndUserParams{
+		ID:     databaseID,
+		UserID: userID,
+	})
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			c.JSON(http.StatusNotFound, gin.H{"error": "Database not found", "code": "NOT_FOUND"})
+			return
+		}
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to fetch database"})
+		return
+	}
+	if row.Provider != "external" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "test-connection applies to external databases", "code": "VALIDATION"})
+		return
+	}
+
+	req := externalDatabaseRequest{
+		Type:     row.Type,
+		Host:     databaseNullString(row.ExternalHost),
+		Port:     int(row.ExternalPort.Int32),
+		Database: databaseNullString(row.ExternalName),
+		Username: databaseNullString(row.ExternalUsername),
+		Password: secrets.Decrypt(row.ExternalPassword),
+		SSL:      row.ExternalSsl,
+	}
+	ctx, cancel := context.WithTimeout(c.Request.Context(), 10*time.Second)
+	defer cancel()
+	latency, probeErr := probeExternalDatabase(ctx, req)
+	if probeErr != nil {
+		c.JSON(http.StatusOK, gin.H{"ok": false, "error": probeErr.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true, "latency_ms": latency.Milliseconds()})
+}
+
+func normalizeExternalRequest(req *externalDatabaseRequest) error {
+	req.Type = normalizeDatabaseType(req.Type)
+	if _, ok := supportedDatabaseTypes[req.Type]; !ok {
+		return fmt.Errorf("%w: %s", errUnsupportedDatabaseType, req.Type)
+	}
+	req.Host = strings.TrimSpace(req.Host)
+	if req.Host == "" {
+		return errors.New("host is required")
+	}
+	if req.Port <= 0 {
+		req.Port = externalDefaultPorts[req.Type]
+	}
+	if req.Port <= 0 || req.Port > 65535 {
+		return errors.New("port must be 1-65535")
+	}
+	return nil
+}
+
+// RegisterExternalDatabase records a database hosted elsewhere — same list,
+// same bind surface, no container. The connection is probed first so typos
+// fail at registration, not at the first service bind.
+func (h *DatabaseHandler) RegisterExternalDatabase(c *gin.Context) {
+	userID, ok := requireAuthenticatedUserID(c)
+	if !ok {
+		return
+	}
+	var req externalDatabaseRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error(), "code": "VALIDATION"})
+		return
+	}
+	req.Name = strings.TrimSpace(req.Name)
+	if req.Name == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "name is required", "code": "VALIDATION"})
+		return
+	}
+	if err := normalizeExternalRequest(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error(), "code": "VALIDATION"})
+		return
+	}
+
+	probeCtx, cancel := context.WithTimeout(c.Request.Context(), 10*time.Second)
+	defer cancel()
+	if _, err := probeExternalDatabase(probeCtx, req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"error": fmt.Sprintf("Connection check failed: %v", err),
+			"code":  "DEPENDENCY_UNAVAILABLE",
+		})
+		return
+	}
+
+	count, err := h.queries.CountDatabaseServicesByUserAndName(c.Request.Context(), sqlcdb.CountDatabaseServicesByUserAndNameParams{
+		UserID: userID,
+		Name:   req.Name,
+	})
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to validate database name"})
+		return
+	}
+	if count > 0 {
+		c.JSON(http.StatusConflict, gin.H{"error": "database name already exists", "code": "CONFLICT"})
+		return
+	}
+
+	databaseID := generateDatabaseID(req.Name)
+	now := sql.NullTime{Time: time.Now(), Valid: true}
+	encPassword := ""
+	if req.Password != "" {
+		encPassword = secrets.Encrypt(req.Password)
+	}
+	if err := h.queries.CreateExternalDatabaseService(c.Request.Context(), sqlcdb.CreateExternalDatabaseServiceParams{
+		ID:               databaseID,
+		UserID:           userID,
+		Name:             req.Name,
+		Type:             req.Type,
+		Version:          "",
+		Plan:             "external",
+		Region:           "external",
+		ExternalHost:     sql.NullString{String: req.Host, Valid: true},
+		ExternalPort:     sql.NullInt32{Int32: int32(req.Port), Valid: true},
+		ExternalName:     sql.NullString{String: req.Database, Valid: req.Database != ""},
+		ExternalUsername: sql.NullString{String: req.Username, Valid: req.Username != ""},
+		ExternalPassword: encPassword,
+		ExternalSsl:      req.SSL,
+		CreatedAt:        now,
+		UpdatedAt:        now,
+	}); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to register database"})
+		return
+	}
+
+	LogAudit(userID, "database", databaseID, "register-external", map[string]interface{}{
+		"name": req.Name,
+		"type": req.Type,
+		"host": req.Host,
+	})
+	c.JSON(http.StatusCreated, gin.H{
+		"id":      databaseID,
+		"message": "External database registered",
+		"status":  "running",
+	})
+}

app/backend/internal/api/dbexternal_test.go

@@ -0,0 +1,97 @@
+package api
+
+import (
+	"context"
+	"net"
+	"testing"
+)
+
+func TestNormalizeExternalRequestDefaults(t *testing.T) {
+	req := externalDatabaseRequest{Type: "PostgreSQL", Host: " db.example.com ", Port: 0}
+	if err := normalizeExternalRequest(&req); err != nil {
+		t.Fatalf("normalize failed: %v", err)
+	}
+	if req.Type != "postgresql" {
+		t.Fatalf("type not normalized: %q", req.Type)
+	}
+	if req.Host != "db.example.com" {
+		t.Fatalf("host not trimmed: %q", req.Host)
+	}
+	if req.Port != 5432 {
+		t.Fatalf("default port = %d, want 5432", req.Port)
+	}
+}
+
+func TestNormalizeExternalRequestRejects(t *testing.T) {
+	cases := []externalDatabaseRequest{
+		{Type: "sqlite", Host: "x"},                  // unsupported type
+		{Type: "postgresql", Host: "  "},             // empty host
+		{Type: "postgresql", Host: "h", Port: 70000}, // out of range
+	}
+	for i, req := range cases {
+		if err := normalizeExternalRequest(&req); err == nil {
+			t.Fatalf("case %d: expected error", i)
+		}
+	}
+}
+
+func TestExternalConnectionURLMasking(t *testing.T) {
+	ext := &DatabaseExternalRef{
+		Host:     "db.example.com",
+		Port:     5432,
+		Database: "appdb",
+		Username: "svc",
+		SSL:      true,
+	}
+	u := externalConnectionURL("postgresql", ext, "s3cret")
+	if u != "postgres://svc:[email protected]:5432/appdb?sslmode=require" {
+		t.Fatalf("unexpected pg url: %s", u)
+	}
+	u = externalConnectionURL("postgresql", ext, "")
+	if u != "postgres://[email protected]:5432/appdb?sslmode=require" {
+		t.Fatalf("unexpected passwordless url: %s", u)
+	}
+
+	r := &DatabaseExternalRef{Host: "cache.internal", Port: 6379, SSL: true}
+	u = externalConnectionURL("redis", r, "pw")
+	if u != "rediss://:[email protected]:6379" {
+		t.Fatalf("unexpected redis url: %s", u)
+	}
+}
+
+func TestProbeExternalDatabaseTCP(t *testing.T) {
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("listen: %v", err)
+	}
+	defer ln.Close()
+	port := ln.Addr().(*net.TCPAddr).Port
+
+	// TCP fallback path — mysql uses a plain dial.
+	latency, err := probeExternalDatabase(context.Background(), externalDatabaseRequest{
+		Type: "mysql", Host: "127.0.0.1", Port: port,
+	})
+	if err != nil {
+		t.Fatalf("probe should succeed against open listener: %v", err)
+	}
+	if latency <= 0 {
+		t.Fatalf("latency not recorded")
+	}
+
+	// Closed port must fail fast.
+	if _, err := probeExternalDatabase(context.Background(), externalDatabaseRequest{
+		Type: "mysql", Host: "127.0.0.1", Port: 1,
+	}); err == nil {
+		t.Fatalf("probe should fail against closed port")
+	}
+}
+
+func TestRedisTLSConfig(t *testing.T) {
+	if redisTLSConfig(false, "h") != nil {
+		t.Fatalf("disabled ssl must produce nil tls config")
+	}
+	cfg := redisTLSConfig(true, "db.example.com")
+	if cfg == nil || cfg.ServerName != "db.example.com" {
+		t.Fatalf("expected ServerName passthrough, got %+v", cfg)
+	}
+}

app/backend/internal/api/routes.go

@@ -383,6 +383,9 @@ func SetupRoutes(router *gin.Engine, db *database.DB, redis *database.Redis, cfg
 			authed.POST("/builds/plan", buildHandler.GetBuildPlan)
 
 			authed.POST("/databases", databaseHandler.CreateDatabase)
+			authed.POST("/databases/register-external", databaseHandler.RegisterExternalDatabase)
+			authed.POST("/databases/test-connection", databaseHandler.TestDatabaseConnection)
+			authed.POST("/databases/:id/test-connection", databaseHandler.TestDatabaseConnectionByID)
 			authed.PUT("/databases/:id", databaseHandler.UpdateDatabase)
 			authed.DELETE("/databases/:id", databaseHandler.DeleteDatabase)
 			authed.POST("/databases/:id/action", databaseHandler.PerformDatabaseAction)

app/backend/internal/cli/commands/databases.go

@@ -196,9 +196,96 @@ var dbDownloadCmd = &cobra.Command{
 	},
 }
 
+var dbRegisterCmd = &cobra.Command{
+	Use:   "register <name>",
+	Short: "Register an external database (probes the connection first)",
+	Args:  cobra.ExactArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		c, err := client()
+		if err != nil {
+			return err
+		}
+		body := map[string]interface{}{"name": args[0]}
+		for _, f := range []string{"type", "host", "database", "username", "password"} {
+			if v, _ := cmd.Flags().GetString(f); v != "" {
+				body[f] = v
+			}
+		}
+		if v, _ := cmd.Flags().GetInt("port"); v > 0 {
+			body["port"] = v
+		}
+		if v, _ := cmd.Flags().GetBool("ssl"); v {
+			body["ssl"] = true
+		}
+		data, err := c.Do("POST", "/databases/register-external", body)
+		if err != nil {
+			return err
+		}
+		if JSONMode() {
+			PrintRaw(data)
+			return nil
+		}
+		m, _ := unwrapObject(data)
+		fmt.Printf("Registered external database %s (%s)\n", args[0], str(m, "id"))
+		return nil
+	},
+}
+
+var dbTestConnCmd = &cobra.Command{
+	Use:   "test-connection [<id>]",
+	Short: "Probe a database connection — by id, or with --type/--host flags",
+	Args:  cobra.MaximumNArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		c, err := client()
+		if err != nil {
+			return err
+		}
+		var data []byte
+		if len(args) == 1 {
+			data, err = c.Do("POST", "/databases/"+args[0]+"/test-connection", map[string]interface{}{})
+		} else {
+			body := map[string]interface{}{}
+			for _, f := range []string{"type", "host", "database", "username", "password"} {
+				if v, _ := cmd.Flags().GetString(f); v != "" {
+					body[f] = v
+				}
+			}
+			if v, _ := cmd.Flags().GetInt("port"); v > 0 {
+				body["port"] = v
+			}
+			if v, _ := cmd.Flags().GetBool("ssl"); v {
+				body["ssl"] = true
+			}
+			data, err = c.Do("POST", "/databases/test-connection", body)
+		}
+		if err != nil {
+			return err
+		}
+		m, _ := unwrapObject(data)
+		if str(m, "ok") == "false" {
+			return &APIError{Message: "connection failed: " + str(m, "error"), ExitCode: ExitError}
+		}
+		if JSONMode() {
+			PrintRaw(data)
+			return nil
+		}
+		fmt.Printf("Connection ok (%sms)\n", str(m, "latency_ms"))
+		return nil
+	},
+}
+
 func init() {
 	dbCreateCmd.Flags().String("type", "postgres", "postgres|mysql|mariadb|mongodb|redis|dragonfly|clickhouse")
 	dbCreateCmd.Flags().String("version", "", "engine version tag")
 	dbCreateCmd.Flags().String("storage-size", "", "volume size (e.g. 10Gi)")
-	DatabasesCmd.AddCommand(dbListCmd, dbGetCmd, dbCreateCmd, dbDeleteCmd, dbActionCmd, dbBackupCmd, dbRestoreCmd, dbDownloadCmd)
+	for _, cmd := range []*cobra.Command{dbRegisterCmd, dbTestConnCmd} {
+		cmd.Flags().String("type", "postgres", "postgres|mysql|mariadb|mongodb|redis|dragonfly|clickhouse")
+		cmd.Flags().String("host", "", "database host")
+		cmd.Flags().Int("port", 0, "database port (default per type)")
+		cmd.Flags().String("database", "", "database name")
+		cmd.Flags().String("username", "", "database username")
+		cmd.Flags().String("password", "", "database password (stored encrypted on register)")
+		cmd.Flags().Bool("ssl", false, "require TLS")
+	}
+	DatabasesCmd.AddCommand(dbListCmd, dbGetCmd, dbCreateCmd, dbRegisterCmd, dbTestConnCmd, dbDeleteCmd, dbActionCmd, dbBackupCmd, dbRestoreCmd, dbDownloadCmd)
 }

app/backend/internal/database/sqlcdb/databases.sql.go

@@ -88,6 +88,52 @@ func (q *Queries) CreateDatabaseService(ctx context.Context, arg CreateDatabaseS
 	return err
 }
 
+const createExternalDatabaseService = `-- name: CreateExternalDatabaseService :exec
+INSERT INTO database_services (id, user_id, name, type, status, version, plan, region,
+    provider, external_host, external_port, external_name, external_username, external_password, external_ssl,
+    created_at, updated_at)
+VALUES ($1, $2, $3, $4, 'running', $5, $6, $7, 'external', $8, $9, $10, $11, $12, $13, $14, $15)
+`
+
+type CreateExternalDatabaseServiceParams struct {
+	ID               string         `json:"id"`
+	UserID           string         `json:"user_id"`
+	Name             string         `json:"name"`
+	Type             string         `json:"type"`
+	Version          string         `json:"version"`
+	Plan             string         `json:"plan"`
+	Region           string         `json:"region"`
+	ExternalHost     sql.NullString `json:"external_host"`
+	ExternalPort     sql.NullInt32  `json:"external_port"`
+	ExternalName     sql.NullString `json:"external_name"`
+	ExternalUsername sql.NullString `json:"external_username"`
+	ExternalPassword string         `json:"external_password"`
+	ExternalSsl      bool           `json:"external_ssl"`
+	CreatedAt        sql.NullTime   `json:"created_at"`
+	UpdatedAt        sql.NullTime   `json:"updated_at"`
+}
+
+func (q *Queries) CreateExternalDatabaseService(ctx context.Context, arg CreateExternalDatabaseServiceParams) error {
+	_, err := q.db.ExecContext(ctx, createExternalDatabaseService,
+		arg.ID,
+		arg.UserID,
+		arg.Name,
+		arg.Type,
+		arg.Version,
+		arg.Plan,
+		arg.Region,
+		arg.ExternalHost,
+		arg.ExternalPort,
+		arg.ExternalName,
+		arg.ExternalUsername,
+		arg.ExternalPassword,
+		arg.ExternalSsl,
+		arg.CreatedAt,
+		arg.UpdatedAt,
+	)
+	return err
+}
+
 const databaseServiceExistsByIDAndUser = `-- name: DatabaseServiceExistsByIDAndUser :one
 SELECT EXISTS(
   SELECT 1 FROM database_services WHERE id = $1 AND user_id = $2
@@ -150,7 +196,7 @@ func (q *Queries) GetDatabaseBackupByIDAndDatabaseAndUser(ctx context.Context, a
 }
 
 const getDatabaseServiceByID = `-- name: GetDatabaseServiceByID :one
-SELECT id, user_id, name, type, status, version, plan, region, connection_url, backup_schedule, next_backup_at, created_at, updated_at
+SELECT database_services.id, database_services.user_id, database_services.name, database_services.type, database_services.status, database_services.version, database_services.plan, database_services.region, database_services.connection_url, database_services.backup_schedule, database_services.next_backup_at, database_services.provider, database_services.external_host, database_services.external_port, database_services.external_name, database_services.external_username, database_services.external_password, database_services.external_ssl, database_services.created_at, database_services.updated_at
 FROM database_services
 WHERE id = $1
 `
@@ -170,6 +216,13 @@ func (q *Queries) GetDatabaseServiceByID(ctx context.Context, id string) (Databa
 		&i.ConnectionUrl,
 		&i.BackupSchedule,
 		&i.NextBackupAt,
+		&i.Provider,
+		&i.ExternalHost,
+		&i.ExternalPort,
+		&i.ExternalName,
+		&i.ExternalUsername,
+		&i.ExternalPassword,
+		&i.ExternalSsl,
 		&i.CreatedAt,
 		&i.UpdatedAt,
 	)
@@ -177,7 +230,7 @@ func (q *Queries) GetDatabaseServiceByID(ctx context.Context, id string) (Databa
 }
 
 const getDatabaseServiceByIDAndUser = `-- name: GetDatabaseServiceByIDAndUser :one
-SELECT id, user_id, name, type, status, version, plan, region, connection_url, backup_schedule, next_backup_at, created_at, updated_at
+SELECT database_services.id, database_services.user_id, database_services.name, database_services.type, database_services.status, database_services.version, database_services.plan, database_services.region, database_services.connection_url, database_services.backup_schedule, database_services.next_backup_at, database_services.provider, database_services.external_host, database_services.external_port, database_services.external_name, database_services.external_username, database_services.external_password, database_services.external_ssl, database_services.created_at, database_services.updated_at
 FROM database_services
 WHERE id = $1 AND user_id = $2
 `
@@ -202,6 +255,13 @@ func (q *Queries) GetDatabaseServiceByIDAndUser(ctx context.Context, arg GetData
 		&i.ConnectionUrl,
 		&i.BackupSchedule,
 		&i.NextBackupAt,
+		&i.Provider,
+		&i.ExternalHost,
+		&i.ExternalPort,
+		&i.ExternalName,
+		&i.ExternalUsername,
+		&i.ExternalPassword,
+		&i.ExternalSsl,
 		&i.CreatedAt,
 		&i.UpdatedAt,
 	)
@@ -222,7 +282,7 @@ func (q *Queries) GetDatabaseServiceOwnerID(ctx context.Context, id string) (str
 }
 
 const listAllDatabaseServices = `-- name: ListAllDatabaseServices :many
-SELECT id, user_id, name, type, status, version, plan, region, connection_url, backup_schedule, next_backup_at, created_at, updated_at
+SELECT database_services.id, database_services.user_id, database_services.name, database_services.type, database_services.status, database_services.version, database_services.plan, database_services.region, database_services.connection_url, database_services.backup_schedule, database_services.next_backup_at, database_services.provider, database_services.external_host, database_services.external_port, database_services.external_name, database_services.external_username, database_services.external_password, database_services.external_ssl, database_services.created_at, database_services.updated_at
 FROM database_services
 ORDER BY created_at DESC
 `
@@ -248,6 +308,13 @@ func (q *Queries) ListAllDatabaseServices(ctx context.Context) ([]DatabaseServic
 			&i.ConnectionUrl,
 			&i.BackupSchedule,
 			&i.NextBackupAt,
+			&i.Provider,
+			&i.ExternalHost,
+			&i.ExternalPort,
+			&i.ExternalName,
+			&i.ExternalUsername,
+			&i.ExternalPassword,
+			&i.ExternalSsl,
 			&i.CreatedAt,
 			&i.UpdatedAt,
 		); err != nil {
@@ -311,7 +378,7 @@ func (q *Queries) ListDatabaseBackupsByDatabaseAndUser(ctx context.Context, arg
 }
 
 const listDatabaseServicesByUser = `-- name: ListDatabaseServicesByUser :many
-SELECT id, user_id, name, type, status, version, plan, region, connection_url, backup_schedule, next_backup_at, created_at, updated_at
+SELECT database_services.id, database_services.user_id, database_services.name, database_services.type, database_services.status, database_services.version, database_services.plan, database_services.region, database_services.connection_url, database_services.backup_schedule, database_services.next_backup_at, database_services.provider, database_services.external_host, database_services.external_port, database_services.external_name, database_services.external_username, database_services.external_password, database_services.external_ssl, database_services.created_at, database_services.updated_at
 FROM database_services
 WHERE user_id = $1
 ORDER BY created_at DESC
@@ -338,6 +405,13 @@ func (q *Queries) ListDatabaseServicesByUser(ctx context.Context, userID string)
 			&i.ConnectionUrl,
 			&i.BackupSchedule,
 			&i.NextBackupAt,
+			&i.Provider,
+			&i.ExternalHost,
+			&i.ExternalPort,
+			&i.ExternalName,
+			&i.ExternalUsername,
+			&i.ExternalPassword,
+			&i.ExternalSsl,
 			&i.CreatedAt,
 			&i.UpdatedAt,
 		); err != nil {

app/backend/internal/database/sqlcdb/models.go

@@ -91,6 +91,13 @@ type DatabaseService struct {
 	ConnectionUrl    sql.NullString `json:"connection_url"`
 	BackupSchedule   sql.NullString `json:"backup_schedule"`
 	NextBackupAt     sql.NullTime   `json:"next_backup_at"`
+	Provider         string         `json:"provider"`
+	ExternalHost     sql.NullString `json:"external_host"`
+	ExternalPort     sql.NullInt32  `json:"external_port"`
+	ExternalName     sql.NullString `json:"external_name"`
+	ExternalUsername sql.NullString `json:"external_username"`
+	ExternalPassword string         `json:"external_password"`
+	ExternalSsl      bool           `json:"external_ssl"`
 	CreatedAt        sql.NullTime   `json:"created_at"`
 	UpdatedAt        sql.NullTime   `json:"updated_at"`
 }
@@ -167,6 +174,17 @@ type ProjectMember struct {
 	CreatedAt sql.NullTime `json:"created_at"`
 }
 
+type Registry struct {
+	ID        uuid.UUID `json:"id"`
+	OwnerID   uuid.UUID `json:"owner_id"`
+	Name      string    `json:"name"`
+	Host      string    `json:"host"`
+	Username  string    `json:"username"`
+	Password  string    `json:"password"`
+	CreatedAt time.Time `json:"created_at"`
+	UpdatedAt time.Time `json:"updated_at"`
+}
+
 type Service struct {
 	ID              uuid.UUID       `json:"id"`
 	Name            string          `json:"name"`
@@ -204,6 +222,11 @@ type Service struct {
 	Volumes         json.RawMessage `json:"volumes"`
 	MaintenanceMode bool            `json:"maintenance_mode"`
 	BasicAuthUsers  string          `json:"basic_auth_users"`
+	Builder         string          `json:"builder"`
+	CpuReserve      string          `json:"cpu_reserve"`
+	MemoryReserve   string          `json:"memory_reserve"`
+	StaticBuildCmd  string          `json:"static_build_cmd"`
+	StaticDir       string          `json:"static_dir"`
 }
 
 type ServiceDomain struct {

app/backend/internal/database/sqlcdb/querier.go

@@ -22,6 +22,7 @@ type Querier interface {
 	CreateContainer(ctx context.Context, arg CreateContainerParams) (ContainerInstance, error)
 	CreateDatabaseBackup(ctx context.Context, arg CreateDatabaseBackupParams) error
 	CreateDatabaseService(ctx context.Context, arg CreateDatabaseServiceParams) error
+	CreateExternalDatabaseService(ctx context.Context, arg CreateExternalDatabaseServiceParams) error
 	CreateNotification(ctx context.Context, arg CreateNotificationParams) error
 	CreateProject(ctx context.Context, arg CreateProjectParams) (Project, error)
 	CreateServiceFromTemplate(ctx context.Context, arg CreateServiceFromTemplateParams) error

app/backend/internal/mcpserver/server.go

@@ -99,6 +99,9 @@ func init() {
 	register(spec{"containr_databases_list", "List managed databases", "GET", "/databases", nil, nil, false})
 	register(spec{"containr_databases_get", "Get a database (connection URL included)", "GET", "/databases/{id}", []string{"id"}, nil, false})
 	register(spec{"containr_databases_create", "Provision a managed database. Args: name, type (postgres|mysql|mariadb|mongodb|redis|dragonfly|clickhouse).", "POST", "/databases", nil, nil, false})
+	register(spec{"containr_databases_register_external", "Register a database hosted elsewhere — probed first, password stored encrypted. Args: name (required), type (required), host (required), port, database, username, password, ssl.", "POST", "/databases/register-external", nil, []string{"name", "type", "host"}, false})
+	register(spec{"containr_databases_test_connection", "Probe a DB connection ad-hoc. Args: type, host (required), port, database, username, password, ssl.", "POST", "/databases/test-connection", nil, []string{"type", "host"}, false})
+	register(spec{"containr_databases_test_connection_by_id", "Re-probe a registered external database with its stored credentials. Args: id.", "POST", "/databases/{id}/test-connection", []string{"id"}, nil, false})
 	register(spec{"containr_databases_action", "Start/stop/restart a database. Args: id, action.", "POST", "/databases/{id}/action", []string{"id"}, []string{"action"}, false})
 	register(spec{"containr_databases_backup", "Take a manual backup snapshot", "POST", "/databases/{id}/backup", []string{"id"}, nil, false})
 	register(spec{"containr_databases_restore", "Restore a database from a backup — overwrites current data. Requires confirm:true.", "POST", "/databases/{id}/restore", []string{"id"}, []string{"backup_id"}, true})

app/backend/migrations_goose/20261013000000_external_databases.sql

@@ -0,0 +1,33 @@
+-- +goose Up
+-- +goose StatementBegin
+ALTER TABLE database_services
+    ADD COLUMN IF NOT EXISTS provider VARCHAR(20) NOT NULL DEFAULT 'managed',
+    ADD COLUMN IF NOT EXISTS external_host VARCHAR(255),
+    ADD COLUMN IF NOT EXISTS external_port INTEGER,
+    ADD COLUMN IF NOT EXISTS external_name VARCHAR(255),
+    ADD COLUMN IF NOT EXISTS external_username VARCHAR(255),
+    ADD COLUMN IF NOT EXISTS external_password TEXT NOT NULL DEFAULT '',
+    ADD COLUMN IF NOT EXISTS external_ssl BOOLEAN NOT NULL DEFAULT false;
+
+ALTER TABLE database_services
+    DROP CONSTRAINT IF EXISTS database_services_plan_check,
+    ADD CONSTRAINT database_services_plan_check
+        CHECK (plan IN ('hobby', 'starter', 'standard', 'business', 'external'));
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+ALTER TABLE database_services
+    DROP CONSTRAINT IF EXISTS database_services_plan_check,
+    ADD CONSTRAINT database_services_plan_check
+        CHECK (plan IN ('hobby', 'starter', 'standard', 'business'));
+
+ALTER TABLE database_services
+    DROP COLUMN IF EXISTS provider,
+    DROP COLUMN IF EXISTS external_host,
+    DROP COLUMN IF EXISTS external_port,
+    DROP COLUMN IF EXISTS external_name,
+    DROP COLUMN IF EXISTS external_username,
+    DROP COLUMN IF EXISTS external_password,
+    DROP COLUMN IF EXISTS external_ssl;
+-- +goose StatementEnd

app/backend/sqlc/queries/databases.sql

@@ -1,16 +1,16 @@
 -- name: ListDatabaseServicesByUser :many
-SELECT id, user_id, name, type, status, version, plan, region, connection_url, backup_schedule, next_backup_at, created_at, updated_at
+SELECT database_services.*
 FROM database_services
 WHERE user_id = $1
 ORDER BY created_at DESC;
 
 -- name: ListAllDatabaseServices :many
-SELECT id, user_id, name, type, status, version, plan, region, connection_url, backup_schedule, next_backup_at, created_at, updated_at
+SELECT database_services.*
 FROM database_services
 ORDER BY created_at DESC;
 
 -- name: GetDatabaseServiceByID :one
-SELECT id, user_id, name, type, status, version, plan, region, connection_url, backup_schedule, next_backup_at, created_at, updated_at
+SELECT database_services.*
 FROM database_services
 WHERE id = $1;
 
@@ -20,7 +20,7 @@ FROM database_services
 WHERE id = $1;
 
 -- name: GetDatabaseServiceByIDAndUser :one
-SELECT id, user_id, name, type, status, version, plan, region, connection_url, backup_schedule, next_backup_at, created_at, updated_at
+SELECT database_services.*
 FROM database_services
 WHERE id = $1 AND user_id = $2;
 
@@ -110,3 +110,9 @@ WHERE backup_schedule IS NOT NULL AND backup_schedule <> ''
 UPDATE database_services
 SET next_backup_at = $1
 WHERE id = $2;
+
+-- name: CreateExternalDatabaseService :exec
+INSERT INTO database_services (id, user_id, name, type, status, version, plan, region,
+    provider, external_host, external_port, external_name, external_username, external_password, external_ssl,
+    created_at, updated_at)
+VALUES ($1, $2, $3, $4, 'running', $5, $6, $7, 'external', $8, $9, $10, $11, $12, $13, $14, $15);

app/backend/sqlc/schema.sql

@@ -139,6 +139,13 @@ CREATE TABLE database_services (
     connection_url TEXT,
     backup_schedule VARCHAR(100),
     next_backup_at TIMESTAMP WITH TIME ZONE,
+    provider VARCHAR(20) NOT NULL DEFAULT 'managed',
+    external_host VARCHAR(255),
+    external_port INTEGER,
+    external_name VARCHAR(255),
+    external_username VARCHAR(255),
+    external_password TEXT NOT NULL DEFAULT '',
+    external_ssl BOOLEAN NOT NULL DEFAULT false,
     created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
     updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
 );

app/frontend/src/features/secondary/pages.tsx

@@ -30,6 +30,10 @@ import {
   createDatabaseBackup,
   restoreDatabaseBackup,
   createManagedDatabase,
+  registerExternalDatabase,
+  testDatabaseConnection,
+  testDatabaseConnectionByID,
+  type ExternalDatabaseInput,
   listServicesByProject,
   listServiceVariables,
   updateServiceVariables,
@@ -1901,7 +1905,11 @@ export function DatabasesPage() {
   const [expandedId, setExpandedId] = useState<string | null>(null);
   const [bindDb, setBindDb] = useState<DatabaseEntity | null>(null);
   const [createOpen, setCreateOpen] = useState(false);
+  const [createMode, setCreateMode] = useState<'managed' | 'external'>('managed');
   const [createForm, setCreateForm] = useState({ name: '', type: 'postgresql', plan: 'hobby', region: 'local' });
+  const [externalForm, setExternalForm] = useState({ name: '', type: 'postgresql', host: '', port: '', database: '', username: '', password: '', ssl: false });
+  const [externalProbe, setExternalProbe] = useState<{ ok: boolean; latency_ms?: number; error?: string } | null>(null);
+  const [externalTestResult, setExternalTestResult] = useState<Record<string, { ok: boolean; latency_ms?: number; error?: string }>>({});
   const [createError, setCreateError] = useState<string | null>(null);
   const databasesQuery = useQuery({
     queryKey: ['databases'],
@@ -1929,6 +1937,40 @@ export function DatabasesPage() {
       setCreateError(error instanceof Error ? error.message : 'Failed to create database');
     },
   });
+  const externalPayload = (): ExternalDatabaseInput => ({
+    name: externalForm.name.trim(),
+    type: externalForm.type,
+    host: externalForm.host.trim(),
+    port: Number(externalForm.port) || undefined,
+    database: externalForm.database.trim() || undefined,
+    username: externalForm.username.trim() || undefined,
+    password: externalForm.password || undefined,
+    ssl: externalForm.ssl,
+  });
+  const registerExternalMutation = useMutation({
+    mutationFn: () => registerExternalDatabase(externalPayload()),
+    onSuccess: () => {
+      setCreateOpen(false);
+      setExternalForm({ name: '', type: 'postgresql', host: '', port: '', database: '', username: '', password: '', ssl: false });
+      setExternalProbe(null);
+      setCreateError(null);
+      invalidate();
+    },
+    onError: (error) => {
+      setCreateError(error instanceof Error ? error.message : 'Failed to register database');
+    },
+  });
+  const probeMutation = useMutation({
+    mutationFn: () => testDatabaseConnection(externalPayload()),
+    onSuccess: (result) => setExternalProbe(result),
+    onError: (error) => setExternalProbe({ ok: false, error: error instanceof Error ? error.message : 'probe failed' }),
+  });
+  const testByIdMutation = useMutation({
+    mutationFn: (id: string) => testDatabaseConnectionByID(id),
+    onSuccess: (result, id) => setExternalTestResult((prev) => ({ ...prev, [id]: result })),
+    onError: (error, id) =>
+      setExternalTestResult((prev) => ({ ...prev, [id]: { ok: false, error: error instanceof Error ? error.message : 'probe failed' } })),
+  });
   const actionMutation = useMutation({
     mutationFn: ({ id, action }: { id: string; action: 'start' | 'stop' | 'restart' }) =>
       databaseAction(id, action),
@@ -2014,9 +2056,16 @@ export function DatabasesPage() {
                       <div className="flex items-center gap-2">
                         <span className="text-sm font-medium text-[var(--text-primary)]">{db.name}</span>
                         <span className="text-xs px-1.5 py-0.5 rounded bg-[var(--surface-muted)] text-[var(--text-secondary)] mono">{db.type}{db.version ? ` ${db.version}` : ''}</span>
+                        {db.provider === 'external' && (
+                          <span className="text-xs px-1.5 py-0.5 rounded bg-[var(--accent-primary-soft)] text-[var(--accent-primary)]">external</span>
+                        )}
                         <span className={`text-xs px-1.5 py-0.5 rounded ${dbStatusClass[db.status ?? ''] ?? 'bg-[var(--surface-muted)] text-[var(--text-muted)]'}`}>{db.status}</span>
                       </div>
-                      <p className="mt-0.5 text-xs text-[var(--text-muted)]">{db.plan} · {db.region}</p>
+                      <p className="mt-0.5 text-xs text-[var(--text-muted)]">
+                        {db.provider === 'external' && db.external
+                          ? `${db.external.host}:${db.external.port}${db.external.database ? ` · ${db.external.database}` : ''}`
+                          : `${db.plan} · ${db.region}`}
+                      </p>
                     </div>
                     <ChevronDown size={15} className={`shrink-0 text-[var(--text-muted)] transition-transform ${expanded ? 'rotate-180' : ''}`} />
                   </button>
@@ -2044,6 +2093,25 @@ export function DatabasesPage() {
                         {signedIn ? (
                           <>
                         <span className="text-xs font-medium uppercase tracking-wider text-[var(--text-muted)] mr-1">Actions</span>
+                        {db.provider === 'external' ? (
+                          <>
+                            <button
+                              onClick={() => testByIdMutation.mutate(db.id ?? '')}
+                              disabled={testByIdMutation.isPending}
+                              className="flex items-center gap-1.5 px-3 py-1.5 rounded-[var(--radius-md)] border border-[var(--border-subtle)] text-xs font-medium text-[var(--text-secondary)] hover:border-[var(--border-default)] disabled:opacity-40 transition-colors"
+                            >
+                              <RefreshCw size={11} /> Test connection
+                            </button>
+                            {externalTestResult[db.id ?? ''] && (
+                              <span className={`text-xs ${externalTestResult[db.id ?? '']?.ok ? 'text-[var(--success)]' : 'text-[var(--error)]'}`}>
+                                {externalTestResult[db.id ?? '']?.ok
+                                  ? `reachable (${externalTestResult[db.id ?? '']?.latency_ms ?? 0}ms)`
+                                  : `unreachable — ${externalTestResult[db.id ?? '']?.error ?? 'probe failed'}`}
+                              </span>
+                            )}
+                          </>
+                        ) : (
+                          <>
                         <button
                           onClick={() => actionMutation.mutate({ id: db.id ?? '', action: 'start' })}
                           disabled={running || actionMutation.isPending}
@@ -2065,6 +2133,8 @@ export function DatabasesPage() {
                         >
                           <RefreshCw size={11} /> Restart
                         </button>
+                          </>
+                        )}
                         <button
                           onClick={() => setBindDb(bindDb?.id === db.id ? null : db)}
                           disabled={!db.connection_url}
@@ -2107,6 +2177,7 @@ export function DatabasesPage() {
                         </div>
                       )}
 
+                      {db.provider !== 'external' && (
                       <div>
                         <div className="mb-2 flex items-center justify-between">
                           <p className="text-xs font-medium uppercase tracking-wider text-[var(--text-muted)]">Backups</p>
@@ -2163,6 +2234,7 @@ export function DatabasesPage() {
                           </p>
                         )}
                       </div>
+                      )}
                     </div>
                   )}
                 </div>
@@ -2177,18 +2249,125 @@ export function DatabasesPage() {
           <div className="w-full max-w-md overflow-hidden rounded-[var(--radius-lg)] border border-[var(--border-subtle)] bg-[var(--bg-base)] shadow-2xl">
             <div className="border-b border-[var(--border-subtle)] px-5 py-4">
               <h2 className="text-[15px] font-semibold text-[var(--text-primary)]">New database</h2>
-              <p className="text-xs text-[var(--text-tertiary)]">Provision a managed database service.</p>
+              <div className="mt-3 flex gap-1 rounded-[var(--radius-md)] border border-[var(--border-subtle)] bg-[var(--surface-muted)] p-1">
+                {(['managed', 'external'] as const).map((mode) => (
+                  <button
+                    key={mode}
+                    type="button"
+                    onClick={() => { setCreateMode(mode); setCreateError(null); }}
+                    className={`flex-1 rounded-[calc(var(--radius-md)-2px)] px-3 py-1.5 text-xs font-medium capitalize transition-colors ${createMode === mode ? 'bg-[var(--bg-base)] text-[var(--text-primary)] shadow-sm' : 'text-[var(--text-muted)] hover:text-[var(--text-secondary)]'}`}
+                  >
+                    {mode}
+                  </button>
+                ))}
+              </div>
+              <p className="mt-2 text-xs text-[var(--text-tertiary)]">
+                {createMode === 'managed' ? 'Provision a managed database service.' : 'Register a database hosted outside Containr.'}
+              </p>
             </div>
             <div className="space-y-4 px-5 py-4">
               <div>
                 <label className="mb-1.5 block text-xs font-medium uppercase tracking-wider text-[var(--text-muted)]">Name</label>
                 <input
-                  value={createForm.name}
+                  value={createMode === 'managed' ? createForm.name : externalForm.name}
-                  onChange={(e) => setCreateForm((f) => ({ ...f, name: e.target.value }))}
+                  onChange={(e) => (createMode === 'managed' ? setCreateForm((f) => ({ ...f, name: e.target.value })) : setExternalForm((f) => ({ ...f, name: e.target.value })))}
                   placeholder="my-postgres"
                   className="h-10 w-full rounded-[var(--radius-md)] border border-[var(--border-subtle)] bg-[var(--surface-muted)] px-3 text-sm focus:border-[var(--accent-primary)]"
                 />
               </div>
+              {createMode === 'external' ? (
+                <>
+                  <div className="grid grid-cols-3 gap-3">
+                    <div>
+                      <label className="mb-1.5 block text-xs font-medium uppercase tracking-wider text-[var(--text-muted)]">Type</label>
+                      <select
+                        value={externalForm.type}
+                        onChange={(e) => setExternalForm((f) => ({ ...f, type: e.target.value }))}
+                        className="h-10 w-full rounded-[var(--radius-md)] border border-[var(--border-subtle)] bg-[var(--surface-muted)] px-2 text-sm focus:border-[var(--accent-primary)]"
+                      >
+                        {DATABASE_TYPES.map((t) => (
+                          <option key={t} value={t}>{t}</option>
+                        ))}
+                      </select>
+                    </div>
+                    <div className="col-span-2">
+                      <label className="mb-1.5 block text-xs font-medium uppercase tracking-wider text-[var(--text-muted)]">Host</label>
+                      <input
+                        value={externalForm.host}
+                        onChange={(e) => setExternalForm((f) => ({ ...f, host: e.target.value }))}
+                        placeholder="db.example.com"
+                        className="h-10 w-full rounded-[var(--radius-md)] border border-[var(--border-subtle)] bg-[var(--surface-muted)] px-3 text-sm focus:border-[var(--accent-primary)]"
+                      />
+                    </div>
+                  </div>
+                  <div className="grid grid-cols-2 gap-3">
+                    <div>
+                      <label className="mb-1.5 block text-xs font-medium uppercase tracking-wider text-[var(--text-muted)]">Port</label>
+                      <input
+                        value={externalForm.port}
+                        onChange={(e) => setExternalForm((f) => ({ ...f, port: e.target.value }))}
+                        placeholder="default"
+                        className="h-10 w-full rounded-[var(--radius-md)] border border-[var(--border-subtle)] bg-[var(--surface-muted)] px-3 text-sm focus:border-[var(--accent-primary)]"
+                      />
+                    </div>
+                    <div>
+                      <label className="mb-1.5 block text-xs font-medium uppercase tracking-wider text-[var(--text-muted)]">Database</label>
+                      <input
+                        value={externalForm.database}
+                        onChange={(e) => setExternalForm((f) => ({ ...f, database: e.target.value }))}
+                        placeholder="optional"
+                        className="h-10 w-full rounded-[var(--radius-md)] border border-[var(--border-subtle)] bg-[var(--surface-muted)] px-3 text-sm focus:border-[var(--accent-primary)]"
+                      />
+                    </div>
+                  </div>
+                  <div className="grid grid-cols-2 gap-3">
+                    <div>
+                      <label className="mb-1.5 block text-xs font-medium uppercase tracking-wider text-[var(--text-muted)]">Username</label>
+                      <input
+                        value={externalForm.username}
+                        onChange={(e) => setExternalForm((f) => ({ ...f, username: e.target.value }))}
+                        placeholder="optional"
+                        className="h-10 w-full rounded-[var(--radius-md)] border border-[var(--border-subtle)] bg-[var(--surface-muted)] px-3 text-sm focus:border-[var(--accent-primary)]"
+                      />
+                    </div>
+                    <div>
+                      <label className="mb-1.5 block text-xs font-medium uppercase tracking-wider text-[var(--text-muted)]">Password</label>
+                      <input
+                        type="password"
+                        value={externalForm.password}
+                        onChange={(e) => setExternalForm((f) => ({ ...f, password: e.target.value }))}
+                        placeholder="optional"
+                        className="h-10 w-full rounded-[var(--radius-md)] border border-[var(--border-subtle)] bg-[var(--surface-muted)] px-3 text-sm focus:border-[var(--accent-primary)]"
+                      />
+                    </div>
+                  </div>
+                  <label className="flex items-center gap-2 text-xs text-[var(--text-secondary)]">
+                    <input
+                      type="checkbox"
+                      checked={externalForm.ssl}
+                      onChange={(e) => setExternalForm((f) => ({ ...f, ssl: e.target.checked }))}
+                      className="accent-[var(--accent-primary)]"
+                    />
+                    Require TLS/SSL
+                  </label>
+                  <div className="flex items-center gap-2">
+                    <button
+                      type="button"
+                      onClick={() => probeMutation.mutate()}
+                      disabled={probeMutation.isPending || externalForm.host.trim().length === 0}
+                      className="inline-flex items-center gap-1.5 rounded-[var(--radius-md)] border border-[var(--border-subtle)] px-3 py-1.5 text-xs font-medium text-[var(--text-secondary)] hover:border-[var(--border-default)] disabled:opacity-40"
+                    >
+                      {probeMutation.isPending ? <Loader2 size={12} className="animate-spin" /> : null}
+                      Test connection
+                    </button>
+                    {externalProbe && (
+                      <span className={`text-xs ${externalProbe.ok ? 'text-[var(--success)]' : 'text-[var(--error)]'}`}>
+                        {externalProbe.ok ? `reachable (${externalProbe.latency_ms ?? 0}ms)` : `unreachable — ${externalProbe.error ?? 'probe failed'}`}
+                      </span>
+                    )}
+                  </div>
+                </>
+              ) : (
               <div className="grid grid-cols-3 gap-3">
                 <div>
                   <label className="mb-1.5 block text-xs font-medium uppercase tracking-wider text-[var(--text-muted)]">Type</label>
@@ -2224,6 +2403,7 @@ export function DatabasesPage() {
                   />
                 </div>
               </div>
+              )}
               {createError ? (
                 <div className="rounded-[var(--radius-md)] bg-[var(--error-soft)] px-3.5 py-2.5 text-xs text-[var(--error)]">{createError}</div>
               ) : null}
@@ -2238,12 +2418,15 @@ export function DatabasesPage() {
               </button>
               <button
                 type="button"
-                onClick={() => createMutation.mutate()}
+                onClick={() => (createMode === 'managed' ? createMutation.mutate() : registerExternalMutation.mutate())}
-                disabled={createMutation.isPending || createForm.name.trim().length === 0}
+                disabled={
+                  (createMode === 'managed' ? createMutation.isPending : registerExternalMutation.isPending) ||
+                  (createMode === 'managed' ? createForm.name.trim().length === 0 : externalForm.name.trim().length === 0 || externalForm.host.trim().length === 0)
+                }
                 className="inline-flex items-center gap-1.5 rounded-[var(--radius-md)] bg-[var(--accent-primary)] px-4 py-2 text-xs font-semibold text-[var(--accent-on)] disabled:opacity-50"
               >
-                {createMutation.isPending ? <Loader2 size={13} className="animate-spin" /> : null}
+                {(createMode === 'managed' ? createMutation.isPending : registerExternalMutation.isPending) ? <Loader2 size={13} className="animate-spin" /> : null}
-                Create database
+                {createMode === 'managed' ? 'Create database' : 'Register database'}
               </button>
             </div>
           </div>

app/frontend/src/generated/api-types.ts

@@ -3034,6 +3034,154 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
+    "/databases/register-external": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        put?: never;
+        /**
+         * Register external database
+         * @description Record a database hosted elsewhere — connection is probed first (postgres/redis get protocol-level checks, others TCP). Password stored encrypted, never returned.
+         */
+        post: {
+            parameters: {
+                query?: never;
+                header?: never;
+                path?: never;
+                cookie?: never;
+            };
+            requestBody: {
+                content: {
+                    "application/json": components["schemas"]["ExternalDatabaseRequest"] & Record<string, never>;
+                };
+            };
+            responses: {
+                /** @description External database registered */
+                201: {
+                    headers: {
+                        [name: string]: unknown;
+                    };
+                    content?: never;
+                };
+                /** @description Validation failed or connection probe failed */
+                400: {
+                    headers: {
+                        [name: string]: unknown;
+                    };
+                    content?: never;
+                };
+                /** @description Name already in use */
+                409: {
+                    headers: {
+                        [name: string]: unknown;
+                    };
+                    content?: never;
+                };
+            };
+        };
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
+    "/databases/test-connection": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        put?: never;
+        /**
+         * Probe a database connection
+         * @description Ad-hoc connectivity check — postgres via libpq ping, redis/dragonfly via PING, other engines via TCP dial. Always 200; `ok` carries the result.
+         */
+        post: {
+            parameters: {
+                query?: never;
+                header?: never;
+                path?: never;
+                cookie?: never;
+            };
+            requestBody: {
+                content: {
+                    "application/json": components["schemas"]["ExternalDatabaseRequest"];
+                };
+            };
+            responses: {
+                /** @description Probe result */
+                200: {
+                    headers: {
+                        [name: string]: unknown;
+                    };
+                    content: {
+                        "application/json": {
+                            ok?: boolean;
+                            latency_ms?: number;
+                            error?: string;
+                        };
+                    };
+                };
+            };
+        };
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
+    "/databases/{id}/test-connection": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        put?: never;
+        /**
+         * Re-probe a registered external database
+         * @description Uses the stored credentials. External databases only.
+         */
+        post: {
+            parameters: {
+                query?: never;
+                header?: never;
+                path: {
+                    id: string;
+                };
+                cookie?: never;
+            };
+            requestBody?: never;
+            responses: {
+                /** @description Probe result (`ok` carries the outcome) */
+                200: {
+                    headers: {
+                        [name: string]: unknown;
+                    };
+                    content?: never;
+                };
+                /** @description Database not found */
+                404: {
+                    headers: {
+                        [name: string]: unknown;
+                    };
+                    content?: never;
+                };
+            };
+        };
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/databases/{id}": {
         parameters: {
             query?: never;
@@ -8940,6 +9088,12 @@ export interface components {
             region?: string;
             /** @description Cron expression for automatic backups, empty when unset */
             backup_schedule?: string;
+            /**
+             * @description managed = Containr-provisioned container; external = registered connection to a database hosted elsewhere
+             * @enum {string}
+             */
+            provider?: "managed" | "external";
+            external?: components["schemas"]["DatabaseExternal"];
             /**
              * Format: date-time
              * @description Next scheduled backup run
@@ -8975,6 +9129,28 @@ export interface components {
             /** @description Database region */
             region: string;
         };
+        DatabaseExternal: {
+            host?: string;
+            port?: number;
+            database?: string;
+            username?: string;
+            has_password?: boolean;
+            ssl?: boolean;
+        };
+        ExternalDatabaseRequest: {
+            /** @description Display name (required for register, unused for probes) */
+            name?: string;
+            /** @enum {string} */
+            type: "postgresql" | "redis" | "mysql" | "mariadb" | "mongodb" | "clickhouse" | "dragonfly";
+            host: string;
+            /** @description Defaults to the engine's standard port */
+            port?: number;
+            database?: string;
+            username?: string;
+            /** @description Stored encrypted; never returned */
+            password?: string;
+            ssl?: boolean;
+        };
         UpdateDatabaseRequest: {
             /** @description Updated database name */
             name?: string;

app/frontend/src/generated/docs-snapshot.ts

@@ -40,7 +40,7 @@ export const bundledDocs: BundledDoc[] = [
     "path": "guides/CLI.md",
     "section": "guides",
     "title": "Containr CLI",
-    "markdown": "# Containr CLI\n\nThe CLI controls every part of a Containr instance — the same API surface\nthe web UI uses. Build it with `scripts/build-cli.sh` or\n`go build ./cmd/cli` from `app/backend`.\n\n## Authentication\n\nCreate a personal access token in the web UI under\n**Settings → Personal Access Tokens** (or `containr tokens create`), then:\n\n```bash\ncontainr auth login cnp_...                      # verify + store\ncontainr auth login cnp_... --url https://containr.example.com\ncontainr auth login cnp_... --name production    # named profile\ncontainr auth status                             # show active profile + identity\ncontainr auth logout\n```\n\nResolution order for every command: `--token`/`--api-url` flags >\n`CONTAINR_TOKEN`/`CONTAINR_API_URL` env > active profile >\n`http://localhost:8080/api/v1`. The active profile is `--profile` >\n`CONTAINR_PROFILE` > `current_profile` in `~/.containr.yaml`.\n\n## Output and scripting\n\n- `--json` prints the raw API response — safe to pipe and parse.\n- `--yes` / `-y` skips confirmation on destructive commands (delete,\n  revoke, restore, failover). Non-interactive shells refuse destructive\n  commands without it.\n- Exit codes are stable: `0` ok, `1` error, `2` auth/permission,\n  `3` not found, `4` validation, `5` unreachable.\n\n## Commands\n\n```\nauth login|logout|status         token auth and profiles\ntokens list|create|revoke        personal access tokens\nprojects list|get|create|delete\nservices list|get|create|update|delete|start|stop|restart|redeploy\nservices domains list|add|remove|default|check   multi-domain + DNS preflight\nvolumes list|delete              docker volume inventory + cleanup (admin)\ndeploy <service-id>              trigger a deployment (--no-cache, --commit-hash, --branch)\ndeployments list|get|logs|rollback|cancel\nlogs <service-id> [--follow]     runtime logs (SSE follow)\nexec <service-id> -- <cmd>       one-off container command\nvariables list|set|unset         env vars (secrets masked; --redeploy applies them)\ndatabases list|get|create|delete|action|backup|restore|download-backup\ncron list|get|create|delete|trigger|executions\ntemplates list|get|create|delete|deploy\nnodes list|get|delete|tokens     node agents + onboarding tokens (admin)\nscaling status|policies|services|scale\nha status|alerts|health|policies|enable|disable|failover\nsecurity scan|vulnerabilities|metrics\ngateway services|keys|analytics  (admin)\nadmin overview|users|settings|audit-logs\nnotifications list|read\nup                               deploy the current directory\n```\n\n## containr up\n\nRun inside a git checkout: uses `remote.origin.url` + the current branch\nas the build source, creates a service named after the directory when none\nexists, then triggers a deployment.\n\n```bash\ncontainr up --project <id>\ncontainr up --project <id> --image ghcr.io/example/app:latest   # image, no build\n```\n\nSet `project_id` on the active profile to omit `--project` (stored in\n`~/.containr.yaml` under `profiles.<name>.project_id`).\n\n## Service volumes\n\n`services update` manages mounts; flags replace the whole mount list:\n\n```bash\ncontainr services update <id> --volume data:/data --bind /srv/cfg:/etc/app:ro\ncontainr services update <id> --clear-volumes\n```\n\n`type` is `volume` (docker named volume, auto-created) or `bind` (host\npath). `target` must be absolute. Mounts apply on the next deploy or\nredeploy — `containr deploy <id>` to apply immediately.\n\n`volumes list` shows the node's docker volume inventory with in-use\nflags; `volumes delete <name>` removes an unused volume (admin scope).\n\n## Service domains and access\n\nA service can carry multiple hostnames; the default is mirrored to\n`services.domain`:\n\n```bash\ncontainr services domains add <id> app.example.com --default\ncontainr services domains check <id>      # DNS preflight per domain\ncontainr services domains remove <id> <domain-id>\n```\n\nDNS check compares each domain to the expected target — set\n`app_settings.public_ip` (or `PUBLIC_IP` env) so `wrong-target` is\nmeaningful; without it any resolvable domain reports `ok`.\n\nAccess gates apply via Traefik middlewares (no extra proxy):\n\n```bash\ncontainr services update <id> --maintenance on\ncontainr services update <id> --basic-auth admin:secret --basic-auth ops:pw2\n```\n\nMaintenance mode redirects all traffic to `<BASE_URL>/api/v1/maintenance`\n— set `app_settings.base_url` or `BASE_URL`; without it the service is\ntaken offline with empty responses. Basic-auth credentials are stored\nbcrypt-hashed (htpasswd) and gate every request.\n\n## MCP server\n\n`containr-mcp` (`go build ./cmd/mcp`) exposes the same API as MCP tools\nover stdio — every command group above maps to a `containr_*` tool\n(~60 tools). Destructive tools require the caller to pass\n`confirm: true`; results are pretty JSON with `isError` on failures.\n\nClient configuration (Claude Code, Cursor, Devin, any stdiLine truncated
+    "markdown": "# Containr CLI\n\nThe CLI controls every part of a Containr instance — the same API surface\nthe web UI uses. Build it with `scripts/build-cli.sh` or\n`go build ./cmd/cli` from `app/backend`.\n\n## Authentication\n\nCreate a personal access token in the web UI under\n**Settings → Personal Access Tokens** (or `containr tokens create`), then:\n\n```bash\ncontainr auth login cnp_...                      # verify + store\ncontainr auth login cnp_... --url https://containr.example.com\ncontainr auth login cnp_... --name production    # named profile\ncontainr auth status                             # show active profile + identity\ncontainr auth logout\n```\n\nResolution order for every command: `--token`/`--api-url` flags >\n`CONTAINR_TOKEN`/`CONTAINR_API_URL` env > active profile >\n`http://localhost:8080/api/v1`. The active profile is `--profile` >\n`CONTAINR_PROFILE` > `current_profile` in `~/.containr.yaml`.\n\n## Output and scripting\n\n- `--json` prints the raw API response — safe to pipe and parse.\n- `--yes` / `-y` skips confirmation on destructive commands (delete,\n  revoke, restore, failover). Non-interactive shells refuse destructive\n  commands without it.\n- Exit codes are stable: `0` ok, `1` error, `2` auth/permission,\n  `3` not found, `4` validation, `5` unreachable.\n\n## Commands\n\n```\nauth login|logout|status         token auth and profiles\ntokens list|create|revoke        personal access tokens\nprojects list|get|create|delete\nservices list|get|create|update|delete|start|stop|restart|redeploy\nservices clone|move              duplicate config or re-parent a service\nservices domains list|add|remove|default|check   multi-domain + DNS preflight\nregistries list|add|update|remove  private-image pull credentials\nvolumes list|delete              docker volume inventory + cleanup (admin)\ndeploy <service-id>              trigger a deployment (--no-cache, --commit-hash, --branch)\ndeployments list|get|logs|rollback|cancel\nlogs <service-id> [--follow]     runtime logs (SSE follow)\nexec <service-id> -- <cmd>       one-off container command\nvariables list|set|unset         env vars (secrets masked; --redeploy applies them)\ndatabases list|get|create|delete|action|backup|restore|download-backup\ndatabases register <name>      register an external database (--type --host --port --database --username --password --ssl; probed before storing)\ndatabases test-connection      probe a connection — by id, or ad-hoc flags\ncron list|get|create|delete|trigger|executions\ntemplates list|get|create|delete|deploy\nnodes list|get|delete|tokens     node agents + onboarding tokens (admin)\nscaling status|policies|services|scale\nha status|alerts|health|policies|enable|disable|failover\nsecurity scan|vulnerabilities|metrics\ngateway services|keys|analytics  (admin)\nadmin overview|users|settings|audit-logs\nnotifications list|read\nup                               deploy the current directory\n```\n\n## containr up\n\nRun inside a git checkout: uses `remote.origin.url` + the current branch\nas the build source, creates a service named after the directory when none\nexists, then triggers a deployment.\n\n```bash\ncontainr up --project <id>\ncontainr up --project <id> --image ghcr.io/example/app:latest   # image, no build\n```\n\nSet `project_id` on the active profile to omit `--project` (stored in\n`~/.containr.yaml` under `profiles.<name>.project_id`).\n\n## Service volumes\n\n`services update` manages mounts; flags replace the whole mount list:\n\n```bash\ncontainr services update <id> --volume data:/data --bind /srv/cfg:/etc/app:ro\ncontainr services update <id> --clear-volumes\n```\n\n`type` is `volume` (docker named volume, auto-created) or `bind` (host\npath). `target` must be absolute. Mounts apply on the next deploy or\nredeploy — `containr deploy <id>` to apply immediately.\n\n`volumes list` shows the node's docker volume inventory with in-use\nflags; `volumes delete <name>` removes an unused volume (admin scope).\n\n## Service domains and access\n\nA service can carry multiple hostnames; the default is mirrored to\n`services.domain`:\n\n```bash\ncontainr services domains add <id> app.example.com --default\ncontainr services domains check <id>      # DNS preflight per domain\ncontainr services domains remove <id> <domain-id>\n```\n\nDNS check compares each domain to the expected target — set\n`app_settings.public_ip` (or `PUBLIC_IP` env) so `wrong-target` is\nmeaningful; without it any resolvable domain reports `ok`.\n\nAccess gates apply via Traefik middlewares (no extra proxy):\n\n```bash\ncontainr services update <id> --maintenance on\ncontainr services update <id> --basic-auth admin:secret --basic-auth ops:pw2\n```\n\nMaintenance mode redirects all traffic to `<BASE_URL>/api/v1/maintenance`\n— set `app_settings.base_url` or `BASE_URL`; without it the service is\ntaken offline with empty responses. Basic-auth credentials are stored\nbcrypt-hashed (htpasswd) and gate eLine truncated
   },
   {
     "path": "guides/CLOUDFLARE_SETUP.md",

app/frontend/src/lib/api-client.ts

@@ -1733,6 +1733,39 @@ export async function createManagedDatabase(
   return { id: payload.id, status: payload.status ?? 'building' };
 }
 
+export type ExternalDatabaseInput = {
+  name?: string;
+  type: string;
+  host: string;
+  port?: number;
+  database?: string;
+  username?: string;
+  password?: string;
+  ssl?: boolean;
+};
+
+export async function registerExternalDatabase(input: ExternalDatabaseInput): Promise<{ id: string }> {
+  const payload = await requestJson<{ id?: string }>('/databases/register-external', {
+    method: 'POST',
+    body: JSON.stringify(input),
+  });
+  if (!payload.id) {
+    throw new ApiError('Database response is invalid', 500);
+  }
+  return { id: payload.id };
+}
+
+export async function testDatabaseConnection(input: ExternalDatabaseInput): Promise<{ ok: boolean; latency_ms?: number; error?: string }> {
+  return requestJson('/databases/test-connection', {
+    method: 'POST',
+    body: JSON.stringify(input),
+  });
+}
+
+export async function testDatabaseConnectionByID(id: string): Promise<{ ok: boolean; latency_ms?: number; error?: string }> {
+  return requestJson(`/databases/${encodeURIComponent(id)}/test-connection`, { method: 'POST' });
+}
+
 export type ConnectGitRepositoryInput = components['schemas']['ConnectGitRepoRequest'];
 export type CreateGitWebhookInput = components['schemas']['CreateWebhookRequest'];
 export type GitWebhookEntity = components['schemas']['GitWebhook'];

docs/api/openapi.yaml

@@ -2050,6 +2050,80 @@ paths:
               schema:
                 $ref: '#/components/schemas/DatabaseCreateResponse'
 
+  /databases/register-external:
+    post:
+      tags:
+        - Databases
+      summary: Register external database
+      description: Record a database hosted elsewhere — connection is probed first (postgres/redis get protocol-level checks, others TCP). Password stored encrypted, never returned.
+      security:
+        - bearerAuth: []
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              allOf:
+                - $ref: '#/components/schemas/ExternalDatabaseRequest'
+                - type: object
+                  required: [name]
+      responses:
+        '201':
+          description: External database registered
+        '400':
+          description: Validation failed or connection probe failed
+        '409':
+          description: Name already in use
+
+  /databases/test-connection:
+    post:
+      tags:
+        - Databases
+      summary: Probe a database connection
+      description: Ad-hoc connectivity check — postgres via libpq ping, redis/dragonfly via PING, other engines via TCP dial. Always 200; `ok` carries the result.
+      security:
+        - bearerAuth: []
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/ExternalDatabaseRequest'
+      responses:
+        '200':
+          description: Probe result
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  ok:
+                    type: boolean
+                  latency_ms:
+                    type: integer
+                  error:
+                    type: string
+
+  /databases/{id}/test-connection:
+    post:
+      tags:
+        - Databases
+      summary: Re-probe a registered external database
+      description: Uses the stored credentials. External databases only.
+      security:
+        - bearerAuth: []
+      parameters:
+        - name: id
+          in: path
+          required: true
+          schema:
+            type: string
+      responses:
+        '200':
+          description: Probe result (`ok` carries the outcome)
+        '404':
+          description: Database not found
+
   /databases/{id}:
     get:
       tags:
@@ -6241,6 +6315,12 @@ components:
         backup_schedule:
           type: string
           description: Cron expression for automatic backups, empty when unset
+        provider:
+          type: string
+          enum: [managed, external]
+          description: managed = Containr-provisioned container; external = registered connection to a database hosted elsewhere
+        external:
+          $ref: '#/components/schemas/DatabaseExternal'
         next_backup_at:
           type: string
           format: date-time
@@ -6283,6 +6363,49 @@ components:
           type: string
           description: Database region
 
+    DatabaseExternal:
+      type: object
+      properties:
+        host:
+          type: string
+        port:
+          type: integer
+        database:
+          type: string
+        username:
+          type: string
+        has_password:
+          type: boolean
+        ssl:
+          type: boolean
+
+    ExternalDatabaseRequest:
+      type: object
+      required:
+        - type
+        - host
+      properties:
+        name:
+          type: string
+          description: Display name (required for register, unused for probes)
+        type:
+          type: string
+          enum: [postgresql, redis, mysql, mariadb, mongodb, clickhouse, dragonfly]
+        host:
+          type: string
+        port:
+          type: integer
+          description: Defaults to the engine's standard port
+        database:
+          type: string
+        username:
+          type: string
+        password:
+          type: string
+          description: Stored encrypted; never returned
+        ssl:
+          type: boolean
+
     UpdateDatabaseRequest:
       type: object
       properties:

docs/guides/CLI.md

@@ -48,6 +48,8 @@ logs <service-id> [--follow]     runtime logs (SSE follow)
 exec <service-id> -- <cmd>       one-off container command
 variables list|set|unset         env vars (secrets masked; --redeploy applies them)
 databases list|get|create|delete|action|backup|restore|download-backup
+databases register <name>      register an external database (--type --host --port --database --username --password --ssl; probed before storing)
+databases test-connection      probe a connection — by id, or ad-hoc flags
 cron list|get|create|delete|trigger|executions
 templates list|get|create|delete|deploy
 nodes list|get|delete|tokens     node agents + onboarding tokens (admin)

llms.txt

@@ -21,6 +21,7 @@ Base URL: `https://<host>/api/v1`. OpenAPI: `docs/api/openapi.yaml`.
 - **Builders & resources**: service field `builder` = `auto|railpack|nixpacks|dockerfile|static` (auto detects; static builds assets with `static_build_cmd` and serves `static_dir` via nginx:80). `cpu`/`memory` are hard caps; `cpu_reserve`/`memory_reserve` are soft reservations (CPU shares / MemoryReservation) — empty string clears. `app_settings.default_cpu`/`default_memory` set instance defaults; `app_settings.capacity_policy=block` rejects deploys exceeding node memory (default `warn`).
 - **Clone & move**: `POST /services/{id}/clone` `{name?, project_id?, environment?}` copies config, volumes, domains, access gates, and variables (secret ciphertext verbatim; clone starts stopped). `POST /services/{id}/move` `{project_id}` re-parents a service — both require ownership of source and target; name conflicts → `CONFLICT`. Cloned domains are verbatim copies: the same hostname on two services makes routing ambiguous.
 - **Registries**: `GET|POST /registries`, `PUT|DELETE /registries/{id}` — owner-scoped private-image pull credentials, encrypted at rest, never returned (`has_password` signals presence). `host` matched against the image reference on image deploys (`docker.io` for Docker Hub; scheme/case normalized). Empty `password` on update keeps the stored credential.
+- **External databases**: `POST /databases/register-external` (probes first; `{name,type,host,port,database,username,password,ssl}`), `POST /databases/test-connection` (ad-hoc probe → `{ok,latency_ms,error}`), `POST /databases/{id}/test-connection` (re-probe with stored credentials). Rows carry `provider:"external"` + `external{host,port,database,username,has_password,ssl}`; passwords encrypted at rest, never returned. Lifecycle actions and backups reject external rows — no container exists.
 - **Identifiers**: all ids are UUIDs. Tokens: `cnp_` user PATs, `cagt_` agent onboarding tokens.
 
 ## Core objects