How to secure an app built with v0

What to watch for

v0 is good at interfaces and wires up data quickly. Generated server actions and route handlers often work for the signed-in demo user without checking that the caller may see or change that record.

Every Vercel deployment gets its own URL, including previews of unfinished branches. If previews connect to production data, protect them.

The checklist

1. Add secrets in Vercel → Project → Settings → Environment Variables, without NEXT_PUBLIC_, and read them only in server code.
2. In each server action and route handler, load the session, return early when there is none, and scope queries to the user or organisation.
3. Turn on Deployment Protection for preview deployments, or point previews at a separate database.
4. If you use Supabase, enable row level security on every table and test with the anon key.
5. Add security headers in next.config (Content-Security-Policy, Strict-Transport-Security, X-Content-Type-Options, frame-ancestors).
6. Scan the production URL and recheck each fix.

Questions

Is code generated by v0 secure by default?

It follows common patterns, but authorization depends on your data model, which v0 cannot know. Review every server action that reads or writes data.

Related Defexity checks

• SEC-016: Secret key exposed in public HTML or JavaScript
• SEC-019: API route returns data without authentication
• SEC-005: Content-Security-Policy missing or permissive
• SEC-004: Missing or weak Strict-Transport-Security header
• CODE-008: Server secret exposed through a public env prefix (code check, with GitHub)

Sources

• Vercel docs: Deployment Protection (opens in a new tab)