Is my v0 app secure? A 2-minute self-check

v0 is excellent at turning a prompt into a real Next.js app you can ship on Vercel. The security question shows up later, at the point you wire it to a database and real users. That is where the common gaps appear, and they are easy to miss because the app looks finished.

Here is a quick self-check for the handful of things that actually bite people. None of it needs special tools.

1. Is your database open?

Most v0 apps get their data from Supabase or a similar backend. The most common issue by far is that access rules were never turned on, so the anon key that ships in your page lets anyone read your tables. If you use Supabase, confirm Row Level Security is enabled on every table with a policy that scopes rows to the right user.

2. Is a real secret exposed as a public variable?

In a Next.js app, anything prefixed NEXT_PUBLIC_ is shipped to the browser. That is correct for a publishable key, and wrong for a secret. Open your live app, view source, and search for sk_, service_role, or AIza. If a secret key, service-role key, or model API key is in the bundle, rotate it and read it only in a server route or server action.

3. Are private files reachable?

Try visiting /.env, /.git/config, and your source-map files directly. None of them should load for a stranger. A reachable .env hands over your secrets, and public source maps rebuild your original code.

4. The basics

Confirm HTTPS is enforced with a valid certificate, that you are not shipping a wide-open CORS policy, and that the common security headers are present.

The shortcut

Going through this by hand once is worth it. To make it quick, we built a free scanner: paste your app URL at task-bounty.com/scan and it shows, in a few seconds, exactly what your live app exposes to any visitor. It is read-only, it never logs in, and it works on any JavaScript or TypeScript app, not just v0.

Think of it as a flashlight, not a grade. A clean result means the common, cheap-to-find leaks are not showing, which is the exact set of mistakes that turn into an incident. Worth a look before you share your app widely.