diff --git a/.gitignore b/.gitignore
index ffdfe6fb..d61a0137 100644
--- a/.gitignore
+++ b/.gitignore
@@ -31,4 +31,5 @@ temp/
 
 # Go workspace file
 go.work
-go.work.sum
\ No newline at end of file
+go.work.sum
+data*
diff --git a/compose.yml b/compose.yml
new file mode 100644
index 00000000..b238c8fa
--- /dev/null
+++ b/compose.yml
@@ -0,0 +1,59 @@
+services:
+  pgbackweb:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    ports: 
+      - "8085:8085"
+    env_file:
+      - .env
+    environment:
+      # Core app settings
+      PBW_ENCRYPTION_KEY: ${PBW_ENCRYPTION_KEY}
+      PBW_POSTGRES_CONN_STRING: ${PBW_POSTGRES_CONN_STRING}
+      TZ: ${TZ}
+
+      # Enable OIDC
+      PBW_OIDC_ENABLED: ${PBW_OIDC_ENABLED}
+      PBW_OIDC_ISSUER_URL: ${PBW_OIDC_ISSUER_URL}
+      PBW_OIDC_CLIENT_ID: ${PBW_OIDC_CLIENT_ID}
+      PBW_OIDC_CLIENT_SECRET: ${PBW_OIDC_CLIENT_SECRET}
+      PBW_OIDC_REDIRECT_URL: ${PBW_OIDC_REDIRECT_URL}
+
+      # Optional tuning
+      PBW_OIDC_SCOPES: ${PBW_OIDC_SCOPES}
+      PBW_OIDC_USERNAME_CLAIM: ${PBW_OIDC_USERNAME_CLAIM}
+      PBW_OIDC_EMAIL_CLAIM: ${PBW_OIDC_EMAIL_CLAIM}
+      PBW_OIDC_NAME_CLAIM: ${PBW_OIDC_NAME_CLAIM}
+
+    extra_hosts:
+      - "host.docker.internal:host-gateway"
+
+    depends_on:
+      postgres:
+        condition: service_healthy
+    restart: unless-stopped
+    networks:
+      - default
+      - authentik-network
+
+  postgres:
+    image: postgres:18
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_DB: pgbackweb
+      POSTGRES_PASSWORD: password
+    ports:
+      - "5434:5432"
+    volumes:
+      - ./data:/var/lib/postgresql/18/docker
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U postgres"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+networks:
+  default:
+  authentik-network:
+    external: true
+    name: authentik_authentik-network
\ No newline at end of file
diff --git a/internal/database/migrations/20260828054515_add_users_single_user_invariant.sql b/internal/database/migrations/20260828054515_add_users_single_user_invariant.sql
new file mode 100644
index 00000000..17ae2a17
--- /dev/null
+++ b/internal/database/migrations/20260828054515_add_users_single_user_invariant.sql
@@ -0,0 +1,16 @@
+-- +goose Up
+-- +goose StatementBegin
+DO $$
+BEGIN
+  IF (SELECT COUNT(*) FROM users) > 1 THEN
+    RAISE EXCEPTION E'CRITICAL SECURITY ALERT: PG Back Web found more than one user in the database.\n\nThis instance was probably compromised through the create-first-user endpoint vulnerability, fixed in v0.5.2. PG Back Web refuses to start until the database is cleaned.\n\nTo fix this:\n\n1. List all users to identify the legitimate one:\n\n   SELECT id, name, email, created_at FROM users ORDER BY created_at;\n\n2. Delete every user except the legitimate one (replace the email below with yours):\n\n   DELETE FROM users WHERE email NOT IN (''your-email@example.com'');\n\n3. Rotate ALL credentials stored in PG Back Web: PostgreSQL connection strings and S3 destination keys.\n\n4. Start PG Back Web again.\n\nDeleting a user automatically deletes their sessions too.';
+  END IF;
+END $$;
+
+CREATE UNIQUE INDEX users_single_user_invariant_idx ON users ((true));
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+DROP INDEX IF EXISTS users_single_user_invariant_idx;
+-- +goose StatementEnd
diff --git a/internal/integration/postgres/postgres.go b/internal/integration/postgres/postgres.go
index 97b2d64e..36462beb 100644
--- a/internal/integration/postgres/postgres.go
+++ b/internal/integration/postgres/postgres.go
@@ -92,16 +92,22 @@ func (Client) ParseVersion(version string) (PGVersion, error) {
 }
 
 // Test tests the connection to the PostgreSQL database
-func (Client) Test(version PGVersion, connString string) error {
+func (c Client) Test(version PGVersion, connString string) error {
 	cmd := exec.Command(version.Value.PSQL, connString, "-c", "SELECT 1;")
+	fmt.Printf("Running command: %s %s -c 'SELECT 1;'\n", version.Value.PSQL, connString)
+
 	output, err := cmd.CombinedOutput()
+	fmt.Printf("Command output: %s\n", output)
+
 	if err != nil {
+		fmt.Printf("Command error: %v\n", err)
 		return fmt.Errorf(
 			"error running psql test v%s: %s",
 			version.Value.Version, output,
 		)
 	}
 
+	fmt.Println("PSQL test succeeded")
 	return nil
 }
 
diff --git a/internal/view/middleware/no_index.go b/internal/view/middleware/no_index.go
new file mode 100644
index 00000000..085edbf0
--- /dev/null
+++ b/internal/view/middleware/no_index.go
@@ -0,0 +1,14 @@
+package middleware
+
+import (
+	"github.com/labstack/echo/v4"
+)
+
+// NoIndex sets the X-Robots-Tag header on every response to prevent
+// search engines from indexing the application pages.
+func (m *Middleware) NoIndex(next echo.HandlerFunc) echo.HandlerFunc {
+	return func(c echo.Context) error {
+		c.Response().Header().Set("X-Robots-Tag", "noindex, nofollow")
+		return next(c)
+	}
+}
diff --git a/internal/view/router.go b/internal/view/router.go
index 9af5d15a..24939ee5 100644
--- a/internal/view/router.go
+++ b/internal/view/router.go
@@ -17,6 +17,9 @@ import (
 func MountRouter(app *echo.Echo, servs *service.Service) {
 	mids := middleware.New(servs)
 
+	// Register global middlewares
+	app.Use(mids.NoIndex)
+
 	// Create the base group with the path prefix (if any)
 	baseGroup := app.Group(pathutil.GetPathPrefix())
 
diff --git a/internal/view/web/auth/create_first_user.go b/internal/view/web/auth/create_first_user.go
index 6156b575..a7b2947b 100644
--- a/internal/view/web/auth/create_first_user.go
+++ b/internal/view/web/auth/create_first_user.go
@@ -117,6 +117,25 @@ func createFirstUserPage() nodx.Node {
 func (h *handlers) createFirstUserHandler(c echo.Context) error {
 	ctx := c.Request().Context()
 
+	usersQty, err := h.servs.UsersService.GetUsersQty(ctx)
+	if err != nil {
+		logger.Error("failed to get users qty", logger.KV{
+			"ip":    c.RealIP(),
+			"ua":    c.Request().UserAgent(),
+			"error": err,
+		})
+		return c.String(http.StatusInternalServerError, "Internal server error")
+	}
+	if usersQty > 0 {
+		logger.Error("attempt to create a user when users already exist", logger.KV{
+			"ip": c.RealIP(),
+			"ua": c.Request().UserAgent(),
+		})
+		redirectPath := pathutil.BuildPath("/auth/login")
+		htmx.ServerSetRedirect(c.Response().Header(), redirectPath)
+		return c.Redirect(http.StatusFound, redirectPath)
+	}
+
 	var formData struct {
 		Name                 string `form:"name" validate:"required"`
 		Email                string `form:"email" validate:"required,email"`
@@ -130,7 +149,7 @@ func (h *handlers) createFirstUserHandler(c echo.Context) error {
 		return respondhtmx.ToastError(c, err.Error())
 	}
 
-	_, err := h.servs.UsersService.CreateUser(ctx, dbgen.UsersServiceCreateUserParams{
+	_, err = h.servs.UsersService.CreateUser(ctx, dbgen.UsersServiceCreateUserParams{
 		Name:     formData.Name,
 		Email:    formData.Email,
 		Password: sql.NullString{String: formData.Password, Valid: true},
diff --git a/internal/view/web/auth/router.go b/internal/view/web/auth/router.go
index 8cbeb6eb..d3ceee74 100644
--- a/internal/view/web/auth/router.go
+++ b/internal/view/web/auth/router.go
@@ -22,7 +22,10 @@ func MountRouter(
 	requireNoAuth := parent.Group("", mids.RequireNoAuth)
 
 	requireNoAuth.GET("/create-first-user", h.createFirstUserPageHandler)
-	requireNoAuth.POST("/create-first-user", h.createFirstUserHandler)
+	requireNoAuth.POST("/create-first-user", h.createFirstUserHandler, mids.RateLimit(middleware.RateLimitConfig{
+		Limit:  5,
+		Period: 10 * time.Second,
+	}))
 
 	requireNoAuth.GET("/login", h.loginPageHandler)
 	requireNoAuth.POST("/login", h.loginHandler, mids.RateLimit(middleware.RateLimitConfig{
diff --git a/internal/view/web/layout/common.go b/internal/view/web/layout/common.go
index 4cbb253f..fb679121 100644
--- a/internal/view/web/layout/common.go
+++ b/internal/view/web/layout/common.go
@@ -32,6 +32,7 @@ func commonHead() nodx.Node {
 	return nodx.Group(
 		nodx.Meta(nodx.Charset("utf-8")),
 		nodx.Meta(nodx.Name("viewport"), nodx.Content("width=device-width, initial-scale=1")),
+		nodx.Meta(nodx.Name("robots"), nodx.Content("noindex, nofollow")),
 
 		// Inject path prefix as global JavaScript variable
 		nodx.Script(nodx.Rawf("window.PBW_PATH_PREFIX = '%s';", pathutil.GetPathPrefix())),