feat: add private Docker registry authentication for base images

Add per-app registry credentials that are passed to Docker during image
builds, allowing apps to use base images from private registries.

- New registry_credentials table (migration 007)
- RegistryCredential model with full CRUD operations
- Docker client passes AuthConfigs to ImageBuild when credentials exist
- Deploy service fetches app registry credentials before builds
- Web UI section for managing registry credentials (add/edit/delete)
- Comprehensive unit tests for model and auth config builder
- README updated to list the feature

README.md

@@ -9,6 +9,7 @@ A simple self-hosted PaaS that auto-deploys Docker containers from Git repositor
 - Per-app UUID-based webhook URLs for Gitea integration
 - Branch filtering - only deploy on configured branch changes
 - Environment variables, labels, and volume mounts per app
+- Private Docker registry authentication for base images
 - Docker builds via socket access
 - Notifications via ntfy and Slack-compatible webhooks
 - Simple server-rendered UI with Tailwind CSS

internal/database/migrations/007_add_registry_credentials.sql

@@ -0,0 +1,11 @@
+-- Add registry credentials for private Docker registry authentication during builds
+CREATE TABLE registry_credentials (
+    id INTEGER PRIMARY KEY,
+    app_id TEXT NOT NULL REFERENCES apps(id) ON DELETE CASCADE,
+    registry TEXT NOT NULL,
+    username TEXT NOT NULL,
+    password TEXT NOT NULL,
+    UNIQUE(app_id, registry)
+);
+
+CREATE INDEX idx_registry_credentials_app_id ON registry_credentials(app_id);

internal/docker/auth_test.go

@@ -0,0 +1,96 @@
+package docker //nolint:testpackage // tests unexported buildAuthConfigs
+
+import (
+	"testing"
+)
+
+func TestBuildAuthConfigsEmpty(t *testing.T) {
+	t.Parallel()
+
+	result := buildAuthConfigs(nil)
+	if len(result) != 0 {
+		t.Errorf("expected empty map, got %d entries", len(result))
+	}
+}
+
+func TestBuildAuthConfigsSingle(t *testing.T) {
+	t.Parallel()
+
+	auths := []RegistryAuth{
+		{
+			Registry: "registry.example.com",
+			Username: "user",
+			Password: "pass",
+		},
+	}
+
+	result := buildAuthConfigs(auths)
+
+	if len(result) != 1 {
+		t.Fatalf("expected 1 entry, got %d", len(result))
+	}
+
+	cfg, ok := result["registry.example.com"]
+	if !ok {
+		t.Fatal("expected registry.example.com key")
+	}
+
+	if cfg.Username != "user" {
+		t.Errorf("expected username 'user', got %q", cfg.Username)
+	}
+
+	if cfg.Password != "pass" {
+		t.Errorf("expected password 'pass', got %q", cfg.Password)
+	}
+
+	if cfg.ServerAddress != "registry.example.com" {
+		t.Errorf("expected server address 'registry.example.com', got %q", cfg.ServerAddress)
+	}
+}
+
+func TestBuildAuthConfigsMultiple(t *testing.T) {
+	t.Parallel()
+
+	auths := []RegistryAuth{
+		{Registry: "ghcr.io", Username: "ghuser", Password: "ghtoken"},
+		{Registry: "docker.io", Username: "dkuser", Password: "dktoken"},
+	}
+
+	result := buildAuthConfigs(auths)
+
+	if len(result) != 2 {
+		t.Fatalf("expected 2 entries, got %d", len(result))
+	}
+
+	ghcr := result["ghcr.io"]
+	if ghcr.Username != "ghuser" || ghcr.Password != "ghtoken" {
+		t.Errorf("unexpected ghcr.io config: %+v", ghcr)
+	}
+
+	dkr := result["docker.io"]
+	if dkr.Username != "dkuser" || dkr.Password != "dktoken" {
+		t.Errorf("unexpected docker.io config: %+v", dkr)
+	}
+}
+
+func TestRegistryAuthStruct(t *testing.T) {
+	t.Parallel()
+
+	auth := RegistryAuth{
+		Registry: "registry.example.com",
+		Username: "testuser",
+		Password: "testpass",
+	}
+
+	if auth.Registry != "registry.example.com" {
+		t.Errorf("expected registry 'registry.example.com', got %q", auth.Registry)
+	}
+
+	if auth.Username != "testuser" {
+		t.Errorf("expected username 'testuser', got %q", auth.Username)
+	}
+
+	if auth.Password != "testpass" {
+		t.Errorf("expected password 'testpass', got %q", auth.Password)
+	}
+}

internal/docker/client.go

@@ -20,6 +20,7 @@ import (
 	"github.com/docker/docker/api/types/image"
 	"github.com/docker/docker/api/types/mount"
 	"github.com/docker/docker/api/types/network"
+	"github.com/docker/docker/api/types/registry"
 	"github.com/docker/docker/client"
 	"github.com/docker/docker/pkg/archive"
 	"github.com/docker/go-connections/nat"
@@ -105,12 +106,20 @@ func (c *Client) IsConnected() bool {
 	return c.docker != nil
 }
 
+// RegistryAuth contains authentication credentials for a Docker registry.
+type RegistryAuth struct {
+	Registry string
+	Username string
+	Password string //nolint:gosec // credential field required for registry auth
+}
+
 // BuildImageOptions contains options for building an image.
 type BuildImageOptions struct {
 	ContextDir     string
 	DockerfilePath string
 	Tags           []string
 	LogWriter      io.Writer      // Optional writer for build output
+	RegistryAuths  []RegistryAuth // Optional registry credentials for pulling private base images
 }
 
 // BuildImage builds a Docker image from a context directory.
@@ -161,6 +170,21 @@ type PortMapping struct {
 	Protocol      string // "tcp" or "udp"
 }
 
+// buildAuthConfigs converts RegistryAuth slices into Docker's AuthConfigs map.
+func buildAuthConfigs(auths []RegistryAuth) map[string]registry.AuthConfig {
+	configs := make(map[string]registry.AuthConfig, len(auths))
+
+	for _, auth := range auths {
+		configs[auth.Registry] = registry.AuthConfig{
+			Username:      auth.Username,
+			Password:      auth.Password,
+			ServerAddress: auth.Registry,
+		}
+	}
+
+	return configs
+}
+
 // buildPortConfig converts port mappings to Docker port configuration.
 func buildPortConfig(ports []PortMapping) (nat.PortSet, nat.PortMap) {
 	exposedPorts := make(nat.PortSet)
@@ -513,12 +537,18 @@ func (c *Client) performBuild(
 	}()
 
 	// Build image
-	resp, err := c.docker.ImageBuild(ctx, tarArchive, dockertypes.ImageBuildOptions{
+	buildOpts := dockertypes.ImageBuildOptions{
 		Dockerfile: opts.DockerfilePath,
 		Tags:       opts.Tags,
 		Remove:     true,
 		NoCache:    false,
-	})
+	}
+
+	if len(opts.RegistryAuths) > 0 {
+		buildOpts.AuthConfigs = buildAuthConfigs(opts.RegistryAuths)
+	}
+
+	resp, err := c.docker.ImageBuild(ctx, tarArchive, buildOpts)
 	if err != nil {
 		return "", fmt.Errorf("failed to build image: %w", err)
 	}

internal/handlers/app.go

@@ -148,6 +148,7 @@ func (h *Handlers) HandleAppDetail() http.HandlerFunc {
 		labels, _ := application.GetLabels(request.Context())
 		volumes, _ := application.GetVolumes(request.Context())
 		ports, _ := application.GetPorts(request.Context())
+		registryCreds, _ := application.GetRegistryCredentials(request.Context())
 		deployments, _ := application.GetDeployments(
 			request.Context(),
 			recentDeploymentsLimit,
@@ -168,6 +169,7 @@ func (h *Handlers) HandleAppDetail() http.HandlerFunc {
 			"Labels":              labels,
 			"Volumes":             volumes,
 			"Ports":               ports,
+			"RegistryCredentials": registryCreds,
 			"Deployments":         deployments,
 			"LatestDeployment":    latestDeployment,
 			"WebhookURL":          webhookURL,
@@ -1382,3 +1384,126 @@ func formatDeployKey(pubKey string, createdAt time.Time, appName string) string
 
 	return parts[0] + " " + parts[1] + " " + comment
 }
+
+// HandleRegistryCredentialAdd handles adding a registry credential.
+func (h *Handlers) HandleRegistryCredentialAdd() http.HandlerFunc {
+	return func(writer http.ResponseWriter, request *http.Request) {
+		appID := chi.URLParam(request, "id")
+
+		application, findErr := models.FindApp(request.Context(), h.db, appID)
+		if findErr != nil || application == nil {
+			http.NotFound(writer, request)
+
+			return
+		}
+
+		parseErr := request.ParseForm()
+		if parseErr != nil {
+			http.Error(writer, "Bad Request", http.StatusBadRequest)
+
+			return
+		}
+
+		registryURL := strings.TrimSpace(request.FormValue("registry"))
+		username := strings.TrimSpace(request.FormValue("username"))
+		password := request.FormValue("password")
+
+		if registryURL == "" || username == "" || password == "" {
+			http.Redirect(writer, request, "/apps/"+appID, http.StatusSeeOther)
+
+			return
+		}
+
+		cred := models.NewRegistryCredential(h.db)
+		cred.AppID = appID
+		cred.Registry = registryURL
+		cred.Username = username
+		cred.Password = password
+
+		saveErr := cred.Save(request.Context())
+		if saveErr != nil {
+			h.log.Error("failed to save registry credential", "error", saveErr)
+		}
+
+		http.Redirect(writer, request, "/apps/"+appID, http.StatusSeeOther)
+	}
+}
+
+// HandleRegistryCredentialEdit handles editing an existing registry credential.
+func (h *Handlers) HandleRegistryCredentialEdit() http.HandlerFunc {
+	return func(writer http.ResponseWriter, request *http.Request) {
+		appID := chi.URLParam(request, "id")
+		credIDStr := chi.URLParam(request, "credID")
+
+		credID, parseErr := strconv.ParseInt(credIDStr, 10, 64)
+		if parseErr != nil {
+			http.NotFound(writer, request)
+
+			return
+		}
+
+		cred, findErr := models.FindRegistryCredential(request.Context(), h.db, credID)
+		if findErr != nil || cred == nil || cred.AppID != appID {
+			http.NotFound(writer, request)
+
+			return
+		}
+
+		formErr := request.ParseForm()
+		if formErr != nil {
+			http.Error(writer, "Bad Request", http.StatusBadRequest)
+
+			return
+		}
+
+		registryURL := strings.TrimSpace(request.FormValue("registry"))
+		username := strings.TrimSpace(request.FormValue("username"))
+		password := request.FormValue("password")
+
+		if registryURL == "" || username == "" || password == "" {
+			http.Redirect(writer, request, "/apps/"+appID, http.StatusSeeOther)
+
+			return
+		}
+
+		cred.Registry = registryURL
+		cred.Username = username
+		cred.Password = password
+
+		saveErr := cred.Save(request.Context())
+		if saveErr != nil {
+			h.log.Error("failed to update registry credential", "error", saveErr)
+		}
+
+		http.Redirect(writer, request, "/apps/"+appID, http.StatusSeeOther)
+	}
+}
+
+// HandleRegistryCredentialDelete handles deleting a registry credential.
+func (h *Handlers) HandleRegistryCredentialDelete() http.HandlerFunc {
+	return func(writer http.ResponseWriter, request *http.Request) {
+		appID := chi.URLParam(request, "id")
+		credIDStr := chi.URLParam(request, "credID")
+
+		credID, parseErr := strconv.ParseInt(credIDStr, 10, 64)
+		if parseErr != nil {
+			http.NotFound(writer, request)
+
+			return
+		}
+
+		cred, findErr := models.FindRegistryCredential(request.Context(), h.db, credID)
+		if findErr != nil || cred == nil || cred.AppID != appID {
+			http.NotFound(writer, request)
+
+			return
+		}
+
+		deleteErr := cred.Delete(request.Context())
+		if deleteErr != nil {
+			h.log.Error("failed to delete registry credential", "error", deleteErr)
+		}
+
+		http.Redirect(writer, request, "/apps/"+appID, http.StatusSeeOther)
+	}
+}

internal/models/app.go

@@ -119,6 +119,11 @@ func (a *App) GetWebhookEvents(
 	return FindWebhookEventsByAppID(ctx, a.db, a.ID, limit)
 }
 
+// GetRegistryCredentials returns all registry credentials for the app.
+func (a *App) GetRegistryCredentials(ctx context.Context) ([]*RegistryCredential, error) {
+	return FindRegistryCredentialsByAppID(ctx, a.db, a.ID)
+}
+
 func (a *App) exists(ctx context.Context) bool {
 	if a.ID == "" {
 		return false

internal/models/models_test.go

@@ -23,6 +23,7 @@ const (
 	testBranch    = "main"
 	testValue     = "value"
 	testEventType = "push"
+	testUser      = "user"
 )
 
 func setupTestDB(t *testing.T) (*database.Database, func()) {
@@ -704,6 +705,127 @@ func TestAppGetWebhookEvents(t *testing.T) {
 	assert.Len(t, events, 1)
 }
 
+// RegistryCredential Tests.
+
+func TestRegistryCredentialCreateAndFind(t *testing.T) {
+	t.Parallel()
+
+	testDB, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	app := createTestApp(t, testDB)
+
+	cred := models.NewRegistryCredential(testDB)
+	cred.AppID = app.ID
+	cred.Registry = "registry.example.com"
+	cred.Username = "myuser"
+	cred.Password = "mypassword"
+
+	err := cred.Save(context.Background())
+	require.NoError(t, err)
+	assert.NotZero(t, cred.ID)
+
+	creds, err := models.FindRegistryCredentialsByAppID(
+		context.Background(), testDB, app.ID,
+	)
+	require.NoError(t, err)
+	require.Len(t, creds, 1)
+	assert.Equal(t, "registry.example.com", creds[0].Registry)
+	assert.Equal(t, "myuser", creds[0].Username)
+	assert.Equal(t, "mypassword", creds[0].Password)
+}
+
+func TestRegistryCredentialUpdate(t *testing.T) {
+	t.Parallel()
+
+	testDB, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	app := createTestApp(t, testDB)
+
+	cred := models.NewRegistryCredential(testDB)
+	cred.AppID = app.ID
+	cred.Registry = "old.registry.com"
+	cred.Username = "olduser"
+	cred.Password = "oldpass"
+
+	err := cred.Save(context.Background())
+	require.NoError(t, err)
+
+	cred.Registry = "new.registry.com"
+	cred.Username = "newuser"
+	cred.Password = "newpass"
+
+	err = cred.Save(context.Background())
+	require.NoError(t, err)
+
+	found, err := models.FindRegistryCredential(context.Background(), testDB, cred.ID)
+	require.NoError(t, err)
+	require.NotNil(t, found)
+	assert.Equal(t, "new.registry.com", found.Registry)
+	assert.Equal(t, "newuser", found.Username)
+	assert.Equal(t, "newpass", found.Password)
+}
+
+func TestRegistryCredentialDelete(t *testing.T) {
+	t.Parallel()
+
+	testDB, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	app := createTestApp(t, testDB)
+
+	cred := models.NewRegistryCredential(testDB)
+	cred.AppID = app.ID
+	cred.Registry = "delete.registry.com"
+	cred.Username = testUser
+	cred.Password = "pass"
+
+	err := cred.Save(context.Background())
+	require.NoError(t, err)
+
+	err = cred.Delete(context.Background())
+	require.NoError(t, err)
+
+	creds, err := models.FindRegistryCredentialsByAppID(
+		context.Background(), testDB, app.ID,
+	)
+	require.NoError(t, err)
+	assert.Empty(t, creds)
+}
+
+func TestRegistryCredentialFindByIDNotFound(t *testing.T) {
+	t.Parallel()
+
+	testDB, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	found, err := models.FindRegistryCredential(context.Background(), testDB, 99999)
+	require.NoError(t, err)
+	assert.Nil(t, found)
+}
+
+func TestAppGetRegistryCredentials(t *testing.T) {
+	t.Parallel()
+
+	testDB, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	app := createTestApp(t, testDB)
+
+	cred := models.NewRegistryCredential(testDB)
+	cred.AppID = app.ID
+	cred.Registry = "ghcr.io"
+	cred.Username = testUser
+	cred.Password = "token"
+	_ = cred.Save(context.Background())
+
+	creds, err := app.GetRegistryCredentials(context.Background())
+	require.NoError(t, err)
+	assert.Len(t, creds, 1)
+	assert.Equal(t, "ghcr.io", creds[0].Registry)
+}
+
 // Cascade Delete Tests.
 
 //nolint:funlen // Test function with many assertions - acceptable for integration tests
@@ -749,6 +871,13 @@ func TestCascadeDelete(t *testing.T) {
 		deploy.Status = models.DeploymentStatusSuccess
 		_ = deploy.Save(context.Background())
 
+		regCred := models.NewRegistryCredential(testDB)
+		regCred.AppID = app.ID
+		regCred.Registry = "registry.example.com"
+		regCred.Username = testUser
+		regCred.Password = "pass"
+		_ = regCred.Save(context.Background())
+
 		// Delete app.
 		err := app.Delete(context.Background())
 		require.NoError(t, err)
@@ -778,6 +907,11 @@ func TestCascadeDelete(t *testing.T) {
 			context.Background(), testDB, app.ID, 10,
 		)
 		assert.Empty(t, deployments)
+
+		regCreds, _ := models.FindRegistryCredentialsByAppID(
+			context.Background(), testDB, app.ID,
+		)
+		assert.Empty(t, regCreds)
 	})
 }
 

internal/models/registry_credential.go

@@ -0,0 +1,130 @@
+package models
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+
+	"sneak.berlin/go/upaas/internal/database"
+)
+
+// RegistryCredential represents authentication credentials for a private Docker registry.
+type RegistryCredential struct {
+	db *database.Database
+
+	ID       int64
+	AppID    string
+	Registry string
+	Username string
+	Password string //nolint:gosec // credential field required for registry auth
+}
+
+// NewRegistryCredential creates a new RegistryCredential with a database reference.
+func NewRegistryCredential(db *database.Database) *RegistryCredential {
+	return &RegistryCredential{db: db}
+}
+
+// Save inserts or updates the registry credential in the database.
+func (r *RegistryCredential) Save(ctx context.Context) error {
+	if r.ID == 0 {
+		return r.insert(ctx)
+	}
+
+	return r.update(ctx)
+}
+
+// Delete removes the registry credential from the database.
+func (r *RegistryCredential) Delete(ctx context.Context) error {
+	_, err := r.db.Exec(ctx, "DELETE FROM registry_credentials WHERE id = ?", r.ID)
+
+	return err
+}
+
+func (r *RegistryCredential) insert(ctx context.Context) error {
+	query := "INSERT INTO registry_credentials (app_id, registry, username, password) VALUES (?, ?, ?, ?)"
+
+	result, err := r.db.Exec(ctx, query, r.AppID, r.Registry, r.Username, r.Password)
+	if err != nil {
+		return err
+	}
+
+	id, err := result.LastInsertId()
+	if err != nil {
+		return err
+	}
+
+	r.ID = id
+
+	return nil
+}
+
+func (r *RegistryCredential) update(ctx context.Context) error {
+	query := "UPDATE registry_credentials SET registry = ?, username = ?, password = ? WHERE id = ?"
+
+	_, err := r.db.Exec(ctx, query, r.Registry, r.Username, r.Password, r.ID)
+
+	return err
+}
+
+// FindRegistryCredential finds a registry credential by ID.
+//
+//nolint:nilnil // returning nil,nil is idiomatic for "not found" in Active Record
+func FindRegistryCredential(
+	ctx context.Context,
+	db *database.Database,
+	id int64,
+) (*RegistryCredential, error) {
+	cred := NewRegistryCredential(db)
+
+	row := db.QueryRow(ctx,
+		"SELECT id, app_id, registry, username, password FROM registry_credentials WHERE id = ?",
+		id,
+	)
+
+	err := row.Scan(&cred.ID, &cred.AppID, &cred.Registry, &cred.Username, &cred.Password)
+	if err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return nil, nil
+		}
+
+		return nil, fmt.Errorf("scanning registry credential: %w", err)
+	}
+
+	return cred, nil
+}
+
+// FindRegistryCredentialsByAppID finds all registry credentials for an app.
+func FindRegistryCredentialsByAppID(
+	ctx context.Context,
+	db *database.Database,
+	appID string,
+) ([]*RegistryCredential, error) {
+	query := `
+		SELECT id, app_id, registry, username, password FROM registry_credentials
+		WHERE app_id = ? ORDER BY registry`
+
+	rows, err := db.Query(ctx, query, appID)
+	if err != nil {
+		return nil, fmt.Errorf("querying registry credentials by app: %w", err)
+	}
+
+	defer func() { _ = rows.Close() }()
+
+	var creds []*RegistryCredential
+
+	for rows.Next() {
+		cred := NewRegistryCredential(db)
+
+		scanErr := rows.Scan(
+			&cred.ID, &cred.AppID, &cred.Registry, &cred.Username, &cred.Password,
+		)
+		if scanErr != nil {
+			return nil, scanErr
+		}
+
+		creds = append(creds, cred)
+	}
+
+	return creds, rows.Err()
+}

internal/server/routes.go

@@ -98,6 +98,11 @@ func (s *Server) SetupRoutes() {
 			// Ports
 			r.Post("/apps/{id}/ports", s.handlers.HandlePortAdd())
 			r.Post("/apps/{id}/ports/{portID}/delete", s.handlers.HandlePortDelete())
+
+			// Registry Credentials
+			r.Post("/apps/{id}/registry-credentials", s.handlers.HandleRegistryCredentialAdd())
+			r.Post("/apps/{id}/registry-credentials/{credID}/edit", s.handlers.HandleRegistryCredentialEdit())
+			r.Post("/apps/{id}/registry-credentials/{credID}/delete", s.handlers.HandleRegistryCredentialDelete())
 		})
 	})
 

internal/service/deploy/deploy.go

@@ -830,6 +830,13 @@ func (svc *Service) buildImage(
 	logWriter := newDeploymentLogWriter(ctx, deployment)
 	defer logWriter.Close()
 
+	// Fetch registry credentials for private base images
+	registryAuths, err := svc.buildRegistryAuths(ctx, app)
+	if err != nil {
+		svc.log.Warn("failed to fetch registry credentials", "error", err, "app", app.Name)
+		// Continue without auth — public images will still work
+	}
+
 	// BuildImage creates a tar archive from the local filesystem,
 	// so it needs the container path where files exist, not the host path.
 	imageID, err := svc.docker.BuildImage(ctx, docker.BuildImageOptions{
@@ -837,6 +844,7 @@ func (svc *Service) buildImage(
 		DockerfilePath: app.DockerfilePath,
 		Tags:           []string{imageTag},
 		LogWriter:      logWriter,
+		RegistryAuths:  registryAuths,
 	})
 	if err != nil {
 		svc.notify.NotifyBuildFailed(ctx, app, deployment, err)
@@ -1229,6 +1237,34 @@ func (svc *Service) failDeployment(
 
 // writeLogsToFile writes the deployment logs to a file on disk.
 // Structure: DataDir/logs/<hostname>/<appname>/<appname>_<sha>_<timestamp>.log.txt
+// buildRegistryAuths fetches registry credentials for an app and converts them
+// to Docker RegistryAuth objects for use during image builds.
+func (svc *Service) buildRegistryAuths(
+	ctx context.Context,
+	app *models.App,
+) ([]docker.RegistryAuth, error) {
+	creds, err := app.GetRegistryCredentials(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get registry credentials: %w", err)
+	}
+
+	if len(creds) == 0 {
+		return nil, nil
+	}
+
+	auths := make([]docker.RegistryAuth, 0, len(creds))
+
+	for _, cred := range creds {
+		auths = append(auths, docker.RegistryAuth{
+			Registry: cred.Registry,
+			Username: cred.Username,
+			Password: cred.Password,
+		})
+	}
+
+	return auths, nil
+}
+
 func (svc *Service) writeLogsToFile(app *models.App, deployment *models.Deployment) {
 	if !deployment.Logs.Valid || deployment.Logs.String == "" {
 		return

templates/app_detail.html

@@ -154,6 +154,69 @@
         <div class="hidden">{{ .CSRFField }}</div>
     </div>
 
+    <!-- Registry Credentials -->
+    <div class="card p-6 mb-6">
+        <h2 class="section-title mb-4">Registry Credentials</h2>
+        <p class="text-sm text-gray-500 mb-3">Authenticate to private Docker registries when pulling base images during builds.</p>
+        {{if .RegistryCredentials}}
+        <div class="overflow-x-auto mb-4">
+            <table class="table">
+                <thead class="table-header">
+                    <tr>
+                        <th>Registry</th>
+                        <th>Username</th>
+                        <th>Password</th>
+                        <th class="text-right">Actions</th>
+                    </tr>
+                </thead>
+                <tbody class="table-body">
+                    {{range .RegistryCredentials}}
+                    <tr x-data="{ editing: false }">
+                        <template x-if="!editing">
+                            <td class="font-mono">{{.Registry}}</td>
+                        </template>
+                        <template x-if="!editing">
+                            <td class="font-mono">{{.Username}}</td>
+                        </template>
+                        <template x-if="!editing">
+                            <td class="font-mono text-gray-400">••••••••</td>
+                        </template>
+                        <template x-if="!editing">
+                            <td class="text-right">
+                                <button @click="editing = true" class="text-primary-600 hover:text-primary-800 text-sm mr-2">Edit</button>
+                                <form method="POST" action="/apps/{{$.App.ID}}/registry-credentials/{{.ID}}/delete" class="inline" x-data="confirmAction('Delete this registry credential?')" @submit="confirm($event)">
+                                    {{ $.CSRFField }}
+                                    <button type="submit" class="text-error-500 hover:text-error-700 text-sm">Delete</button>
+                                </form>
+                            </td>
+                        </template>
+                        <template x-if="editing">
+                            <td colspan="4">
+                                <form method="POST" action="/apps/{{$.App.ID}}/registry-credentials/{{.ID}}/edit" class="flex gap-2 items-center">
+                                    {{ $.CSRFField }}
+                                    <input type="text" name="registry" value="{{.Registry}}" required class="input flex-1 font-mono text-sm" placeholder="registry.example.com">
+                                    <input type="text" name="username" value="{{.Username}}" required class="input flex-1 font-mono text-sm" placeholder="username">
+                                    <input type="password" name="password" required class="input flex-1 font-mono text-sm" placeholder="password">
+                                    <button type="submit" class="btn-primary text-sm">Save</button>
+                                    <button type="button" @click="editing = false" class="text-gray-500 hover:text-gray-700 text-sm">Cancel</button>
+                                </form>
+                            </td>
+                        </template>
+                    </tr>
+                    {{end}}
+                </tbody>
+            </table>
+        </div>
+        {{end}}
+        <form method="POST" action="/apps/{{.App.ID}}/registry-credentials" class="flex flex-col sm:flex-row gap-2">
+            {{ .CSRFField }}
+            <input type="text" name="registry" placeholder="registry.example.com" required class="input flex-1 font-mono text-sm">
+            <input type="text" name="username" placeholder="username" required class="input flex-1 font-mono text-sm">
+            <input type="password" name="password" placeholder="password" required class="input flex-1 font-mono text-sm">
+            <button type="submit" class="btn-primary">Add</button>
+        </form>
+    </div>
+
     <!-- Labels -->
     <div class="card p-6 mb-6">
         <h2 class="section-title mb-4">Docker Labels</h2>