Lovable security checklist: The complete pre-deployment guide to protecting your Lovable.dev app.

A Lovable security checklist covers five areas Lovable's Supabase scaffold consistently leaves unsecured: service role key exposure, RLS policy gaps, storage bucket access controls, JWT claim validation, and write endpoint sanitization. Enabling RLS on every Supabase table and validating each policy with a denied-access test are the two fixes that prevent most Lovable data exposure incidents. A researcher found a Lovable app with approximately 18,000 users leaking names, emails, debt amounts, and home addresses because public client access combined with missing RLS enforcement — the default outcome when Supabase is wired up under shipping pressure without a security checklist.

Key Security Risks in Lovable-Built Apps

Missing or partial RLS: Supabase tables without RLS policies are readable by anyone with the anon key. Tables with partial RLS can be read for the wrong rows. Both are production data leaks.

Service role in frontend code: The service role key bypasses all RLS policies by design. When Lovable scaffolds frontend utilities that import the service role key, every row in your database is accessible to any client.

Overly broad PostgREST exposure: Supabase exposes your Postgres tables via a REST API. Without tight RLS, anonymous POST and PATCH requests can write to sensitive tables directly — no auth required.

Misunderstood anon key: The Supabase anon key is designed to be public. But founders often assume its presence is the security layer. It is not. RLS is the security layer. The anon key without RLS is an open database.

Client-sent role flags: AI-generated auth flows sometimes derive user permissions from client-provided fields like role: 'admin' in request bodies. Any user can send that field. Authorization must come from the server session.

Service Role & Secret Hygiene

The most dangerous pattern in any Lovable app is the service role key reaching the browser.

• Keep SUPABASE_SERVICE_ROLE_KEY server-only — never in client components, shared utilities, or NEXT_PUBLIC_ vars.
• Store all third-party API keys in server environment variables only.
• Scan your built JS bundle to confirm no privileged keys are present in client-side code.
• Rotate any key that was committed to git, appeared in a preview deployment, or was pasted into a prompt.

// This is always wrong — service role in client code
const supabase = createClient(
  process.env.NEXT_PUBLIC_SUPABASE_URL!,
  process.env.NEXT_PUBLIC_SUPABASE_SERVICE_ROLE_KEY! // ← bypasses all RLS
);

// Correct — service role stays server-side only
// In a server action or API route:
const supabaseAdmin = createClient(
  process.env.SUPABASE_URL!,
  process.env.SUPABASE_SERVICE_ROLE_KEY!
);

Row Level Security (RLS)

This is the most important section for any Lovable + Supabase app.

• Enable RLS on every table that stores user or business data — not just "sensitive" ones.
• Verify policies block unauthorized reads AND writes with real negative tests.
• Confirm all policies reference auth.uid() and not just auth.role() or a client-provided value.
• Test cross-tenant access by querying another user's records with a valid but different session token.
• Check that select, insert, update, and delete operations are each explicitly scoped.

-- Common mistake: policy compiles but doesn't scope to current user
create policy "users can read team docs"
on team_documents for select
using (team_id in (select team_id from memberships));
-- ↑ Missing auth.uid() — any authenticated user can read all team docs

-- Correct version
create policy "users can read own team docs"
on team_documents for select
using (
  team_id in (
    select team_id from memberships
    where user_id = auth.uid()
  )
);

Authentication & Route Protection

• Require auth checks on every write path, not only page-level guards in the frontend.
• Validate user-to-resource ownership in server actions and API route handlers.
• Reject client-provided role flags — derive authorization from the server session only.
• Test cross-tenant access using modified resource IDs and stale session tokens.
• Confirm Supabase Auth JWT claims are not over-trusted in RLS policies without verification.

Storage Buckets

Lovable storage scaffolding frequently creates public buckets by default.

• Lock every storage bucket to private unless the content is intentionally public (e.g. marketing assets).
• Require signed URLs with short expiry for user-uploaded files, invoices, and exports.
• Scope storage access policies to the authenticated user who owns the file.
• Test that private bucket URLs return 403 without a valid signed token.

-- Storage RLS for private user files
create policy "users can access own files"
on storage.objects for select
using (auth.uid() = owner);

Input Validation & XSS

• Validate all form payloads with Zod or equivalent before any Supabase insert or update.
• Sanitize rich text and markdown content before rendering in React components.
• Deny unknown fields to prevent injected attributes from bypassing business rules.
• Test stored XSS in notes, comments, profile fields, and any user-controlled text rendered in the UI.

CORS & API Configuration

• Restrict allowed origins for custom API routes and Supabase edge functions.
• Disable wildcard CORS on all authenticated endpoints.
• Ensure auth cookies and tokens are scoped to expected domains only.
• Review Supabase edge functions for unintended public accessibility.

Rate Limiting & Abuse Prevention

• Add request limits to login, signup, OTP, and password reset endpoints.
• Throttle write-heavy routes to prevent scripted abuse of your Supabase quota.
• Protect public-facing query routes from scraping by IP and token.
• Monitor spikes in anonymous PostgREST requests — these are often early signs of abuse.

Related Security Checklists

Lovable apps are Supabase-backed by default. Once this checklist is done, review the Supabase security checklist for deeper RLS policy validation and service role auditing. For a full cross-tool pre-launch sweep, use the pre-deploy security checklist for vibe-coded apps.

Run Your Security Audit

Want to know which Lovable-shaped vulnerabilities were quietly introduced into your app during rapid AI shipping?

Ubserve runs a full security audit on your real codebase — maps every issue from this checklist to your actual code, shows where each vulnerability was found, and gives you a fix prompt to paste directly into Lovable and fix it before launch.

Audit my Lovable app for these vulnerabilities

Most breaches in Lovable apps are not caused by one dramatic mistake. They happen because small security gaps — one missing RLS policy, one public bucket, one service role key in the wrong file — stack up quietly while you are focused on shipping features.

Run the audit. Fix what it flags. Launch with confidence.

— Mr. Ballaz, Founder of Ubserve