Most of the tools I write about generate a full stack: frontend, backend, and a database wired up behind it. v0 is a different kind of tool, and I think that difference is worth being explicit about, because the security conversation around it looks almost nothing like the one around Lovable or Bolt.
What v0 actually is
v0 launched from Vercel in 2023 as a generative UI system: describe an interface, get real React and Next.js components back, styled and functional. It's grown a lot since, relaunching in 2025 as a broader platform, but the core of what it does hasn't changed. It's extremely good at the part of an app people actually look at. It doesn't, by default, generate a database, an authentication system, or a set of API routes the way a full-stack builder does.
Why that changes what 'security' even means here
Everything I've written about missing row-level security, exposed service keys, or unguarded admin routes assumes there's a backend generated alongside the frontend, with its own defaults to check. When you build a UI with v0 and then wire it up to a separate backend yourself, whether that's Supabase, Firebase, or something you built by hand, the security posture of your app depends almost entirely on that backend, not on v0 itself. v0 built you a beautiful form. Whether submitting that form checks anything at all is a decision made somewhere else completely.
Where the risk actually shows up
- A frontend built to call an API directly, with the API key or endpoint visible in the component code, because nobody separated 'what the UI needs to display' from 'what should stay server-side.'
- Forms and inputs that look polished and complete, giving a false sense that the feature is finished, when the actual validation and permission checks on the backend haven't been built yet at all.
- A gap between how fast the interface came together and how much slower the backend logic behind it actually got built, which can create a false sense that the whole feature is as far along as the part you can see.
What to actually check if you're using it this way
Don't evaluate v0 the way you'd evaluate a full-stack builder. There's no publish-time scan to lean on here because there's often no backend for it to scan. Instead, treat the UI and the backend as two separate projects that each need their own check: does the interface expose anything it shouldn't (a key, an internal endpoint, an ID pattern that reveals more than intended), and separately, does whatever you connected it to actually enforce the access rules you think it does.
A gorgeous form is not evidence that the thing behind it is safe. It's evidence that the part you can see got built well, which is exactly what v0 is good at, and exactly why it's worth remembering that's the only part it was ever responsible for.