Security best practices for Lovable apps

This page focuses on how to write secure code for Lovable apps and avoid common security mistakes during development. For details on Lovable’s security model, security scans, and findings, see Security overview, Project security view, and the Workspace security center.

How Lovable apps are structured

Lovable apps are built with a clear separation of responsibilities:

Frontend runs in the user’s browser, where users can inspect or change it
Backend code runs server-side and handles validation, authentication, and business logic, as Edge Functions, TanStack Start server functions, or API routes depending on your project
Database uses PostgreSQL with row-level security (RLS) to enforce data access

This separation is the foundation of Lovable’s security model. The sections below follow this structure and highlight common security mistakes at each layer and how to avoid them.

Frontend security basics

All frontend code runs in the user’s browser and can be inspected, modified, or bypassed. Frontend code should never make security decisions.

Do not store secrets in frontend code

Store sensitive values in Secrets instead, which also explains what belongs in .env versus a secret. Secrets stored in frontend code are visible to users and should be considered compromised.

// ❌ Wrong: secrets exposed to anyone
const API_KEY = "sk-1234567890abcdef";
const STRIPE_SECRET = "sk_live_...";

Instead: Ask Lovable to add secrets securely. Read secrets only in server-side code, and keep their values out of responses and logs. Example prompts

Add an API key for Stripe payments securely without exposing it in the frontend code

Review frontend code for exposed secrets, API keys, or sensitive information

Do not rely on frontend validation for security

Frontend validation improves user experience but provides no security guarantees.

// ❌ Wrong: client-side validation can be bypassed
const validateUser = (userData) => userData.email.includes("@");

Instead: Validate incoming data in server-side code before using it. Always treat client input as untrusted. Validate formats, enforce business rules, and handle inputs safely on the server before processing or storing data. Example prompts

Move validation logic from React components to server-side code for better security

Identify client-side validation that should be moved to the backend

Backend security with server-side code

Edge Functions run on the server, so you can use them for sensitive logic and credentials. TanStack Start projects can also use server functions and API routes. Every server function or API route must check who is calling and whether they may perform the action. Put authorization, input validation, and calls that require private credentials in server-side code. A function running on the server is still callable by a client, so server-side execution alone does not make the operation private. Use server-side code to handle:

Authentication and authorization
Verify who is making a request and whether they are allowed to perform the action.
Data validation and sanitization
Treat all input as untrusted and enforce business rules consistently.
Business logic and workflows
Handle multi-step processes like registrations, payments, approvals, and state transitions.
Integration with external services
Call third-party APIs securely and keep credentials out of the browser.
Sensitive data processing
Process personal or financial data safely, avoid exposing it unintentionally, and log important security events.

Apply these checks to every relevant endpoint, including functions called directly without going through your app’s UI. Example prompts

Create a server-side function for user registration with proper validation and security checks

Move payment processing logic from the frontend to a secure server-side function

Build a server-side file upload handler with type and size validation

Database security with RLS

You can inspect every policy in your project under More → Database → Manage → Policies (details). Row-level security (RLS) controls who can read or modify individual rows in your database. It applies to requests your app makes on behalf of a signed-in or anonymous user. Server-side code that uses the service role, the privileged database access your backend has, bypasses RLS, so that code must check permissions itself. Lovable sets up basic RLS policies automatically, but you should review and adjust them early in development. RLS is much easier to change before real data exists, and policies are most effective when they stay focused on access control rather than complex business logic.

Common RLS patterns

Most Lovable apps fit into a small set of access patterns:

Personal data: users can access only their own data
Team-based access: team members share access to team data
Public content with ownership: anyone can read, only owners can modify
Organization-based access: users access data within their organization

Design your tables and policies around these patterns whenever possible.

RLS checks before publishing

Before going live, verify:

RLS is enabled on all sensitive tables
Users cannot access other users’ private data
Shared and public data behaves as intended
New tables are not missing policies

Review RLS-related findings in Project security view. Example prompts

Review RLS policies to ensure users can only access their own data and shared data is properly protected

Add RLS policies to the settings table so users can only access their own settings

Set up RLS for teams and projects so team members only see projects from their team

Authentication security basics

All authentication decisions must happen server-side, not in the browser. Client-side authentication checks can be inspected, modified, or bypassed by users and should never be relied on for access control. Enforce authentication in server-side code, where sessions and tokens can be verified securely and consistently.

// ❌ Wrong: client-side authentication checks
const isAuthenticated = localStorage.getItem("authToken") !== null;
if (isAuthenticated) showAdminPanel();

// ✅ Correct: server-side validation
const { user } = await supabase.auth.getUser();
if (!user) {
  return new Response("Unauthorized", { status: 401 });
}

Authentication best practices

Validate authentication and session tokens in server-side code
Check roles and permissions server-side
Use built-in session management for secure token handling
Redirect users to login when sessions expire, but always validate on the server first
Use frontend auth state only to control UI, never to enforce access

Workspace security

For applications that should not be publicly accessible:

Set project access to workspace
Verify the app is not published publicly
Require authentication even for internal tools
Regularly audit who has access

For workspace-wide monitoring, use the Security center.

Security checklist before publishing

Before publishing your app, confirm:

No secrets exist in frontend code
All validation and critical logic runs in server-side code
Row-level security (RLS) policies are configured and tested
Authentication is enforced server-side
Internal apps have workspace visibility
All critical findings in the Security view are addressed
External API calls happen server-side

Security is an ongoing process.Review these practices whenever you add features, change authentication, modify data access, or introduce new external integrations.Regularly reviewing server-side code, row-level security policies, and authentication flows helps prevent regressions over time.

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Guides & reference

Security best practices for Lovable apps

How Lovable apps are structured

Frontend security basics

Do not store secrets in frontend code

Do not rely on frontend validation for security

Backend security with server-side code

Database security with RLS

Common RLS patterns

RLS checks before publishing

Authentication security basics

Workspace security

Security checklist before publishing