v0, honestly.
v0 is the best prompt-to-frontend tool we have reviewed. The React it writes is genuinely good. The layers it does not own, auth, data, secrets, are where v0 apps fail reviews.
The strongest first draft in the game.
- Prompt to clean, modern UI in minutes, with design quality most tools cannot touch.
- Sensible React and Next.js patterns: well-structured, accessible components a team can actually keep.
- Fits the shadcn and Tailwind ecosystem teams already use, so the output drops into real projects.
- Honest scope: it is built for UI and frontend logic, and it nails exactly that.
Built for the frontend. Everything else is yours.
- The backend, data model and infrastructure are out of scope. v0 scaffolds around them, it does not own them.
- Auth flows get generated without guaranteed server-side enforcement.
- Generated queries default permissive, which works in a demo and leaks in production.
- Input validation is often missing on forms, params, uploads and webhooks.
Backend and data-layer issues, not frontend ones.
- Auth checks that exist only in the UI: the route is hidden, but the API still answers anyone who calls it directly.
- Missing row-level security: change an ID, read someone else's data. Common with Supabase and Postgres backends.
- Keys prefixed
NEXT_PUBLIC_get bundled and shipped to every visitor. Mark secrets sensitive on Vercel and rotate anything that leaked. The April 2026 Vercel env-var incident is the reminder that secret hygiene matters regardless of tool. More in our exposed API keys guide. - Unvalidated input: AI failed to defend against XSS in 86% of relevant samples (Veracode, 2025).
- Verbose errors handing stack traces to the client, leaking exactly how the system works.
When the UI needs a production backend.
Call us when the v0 frontend needs real users behind it: server-enforced auth, a locked-down data layer, secrets done right, validation everywhere. We keep your frontend, it is usually the best part, and build production around it. The $500 Week-1 Build Audit is credited against any build; the Go-Live Intensive runs from $14,000.
Is v0 by Vercel safe to use?
Yes, and the frontend code it generates is genuinely usable. The risk is shipping it unchanged: v0 does not enforce server-side auth, lock down your database or validate input, so those layers need hardening before production.
Can I put a v0 app into production directly?
Not without a security pass. Verify auth on the server, enable row-level security, get secrets off the client and validate every input path first. Roughly 45% of AI-generated code ships a known vulnerability.
Do I need to rebuild a v0 app to make it secure?
Usually not. v0 frontends are typically sound. The work is the backend: auth, data access, secrets and validation. Rebuild a layer only if the data model itself is unsafe.
$500 Week-1 audit · credited against any build