Probably not yet — and that is not a criticism of you or of v0. If you are asking "is my v0 app secure" a few days before launch, the most useful thing to know is that v0 hands you no database, no login and no permission rules until you ask for them. It starts you with a Next.js app. Everything security-related arrived later, one prompt at a time. So the question is not "did v0 configure something badly" but "did anyone ever write the rule at all". Five things to check: an exported function marked 'use server' is its own entry point, not covered by the page it sits behind; nothing underneath your app checks permissions unless you set that up; anything named NEXT_PUBLIC_ is printed into files visitors download; pages can quietly ship whole database rows to the browser; and a single gate file at the front of the app is not a lock. Below is how to check each one without being able to read code well.
What v0 actually hands you
v0 describes itself as an agent for building full‑stack apps, and what it generates is overwhelmingly a Next.js app: React, TypeScript, Tailwind, shadcn/ui. There is no separate backend server — the backend is the same app, using what Next.js calls Server Actions and Route Handlers (code that runs on the server instead of in the visitor's browser). A database is opt‑in, added from the Project menu under Settings and Integrations; the providers on offer have grown over time and currently include Supabase, Neon, Upstash, Vercel Blob and Snowflake. Login is opt‑in too — commonly Auth.js, Clerk or Supabase Auth, depending on what you asked for. If you read an older article saying v0 only makes front‑end components and cannot produce a backend, that was true a couple of years ago and is not how v0 works now.
1. Every exported "use server" function is its own entry point
This is the v0‑specific one. In the code panel, search for use server. Each exported function in those files becomes a POST endpoint of its own once your app references it, reachable by anyone who can read the JavaScript your app already sends to the browser. Next.js says this in its own documentation: a Server Action is reachable via a direct POST request, not just through your application's UI. The same page notes the limit of that — an action nothing in your app references is stripped out at build and never gets an endpoint — so the ones to look at are the actions your app actually uses.
The trap is that an admin page which redirects logged‑out visitors still contains actions that must check the visitor themselves. The redirect controls what gets drawn on screen; it does not guard the function. Next.js states this outright: a page‑level authentication check does not extend to the Server Actions defined within it. So for each action, look for two things in the function body itself, not in the page around it. First: does it check who is calling? Second, and more often missing: does it check that this particular person owns the thing they named? An action that takes an id and deletes or updates that row without asking whose row it is will let any logged‑in user operate on anyone else's data.
2. There is no safety net under the app unless you built one
If you have read advice for apps built with Lovable, it centres on Row Level Security — rules stored in the database itself. That advice does not transfer automatically. Find your database connection variable first, because the answer splits:
If it is Neon or plain Postgres, a rule layer exists but nothing switches it on for you. Postgres has row‑level security built in and Neon ships its own JWT‑based version of it, but policies do nothing until you write them, and by default the table's owner bypasses them anyway — which is the role an ordinary connection string usually connects as. So unless someone deliberately set that up, every permission decision lives in the app code, and if one query forgets to ask "whose row is this?", nothing downstream catches it. v0 will generate and run SQL for you, so expect to see queries written out as text rather than through an ORM. Read each one and check the filtering: a query that selects by an id the browser supplied, with nothing tying it to the current user, is the bug.
If it is Supabase, you are in familiar territory and the usual database‑rules advice applies, plus one extra: the service role key bypasses row‑level security by design, so it must never appear in code the browser can reach. Our write‑up on Lovable and Supabase covers that side in more detail.
3. Keys baked into the page
In Next.js, an environment variable (a setting stored outside your code, such as a password or key) whose name starts with NEXT_PUBLIC_ is deliberately visible to the browser. Worse, the value is not looked up when someone visits — it is inlined into the JavaScript at build time and shipped with it.
Two things follow. Judge each one by what it is, not by its name: a Stripe publishable key or an analytics ID is designed to be public and is fine, while a database URL, an AI provider key, or a service role key is not. And if you find a real secret there, changing the variable is not enough. Rotate the key at the provider and redeploy, because the already‑built files still carry the old value.
There is a Next.js‑only version of this mistake, and it works the other way round from what you might expect. A secret read in a file that later gains 'use client' is not shipped to the browser — Next.js replaces any variable without the NEXT_PUBLIC_ prefix with an empty string in the client bundle. The danger is what happens next: the feature silently breaks, and the obvious fix is to rename the variable with a NEXT_PUBLIC_ prefix, which really does publish it. Search for files containing both 'use client' and process.env and check what was done about each one. Vercel says v0 runs security checks before deploying and has blocked deployments over exposed secrets — over 17,000 in July 2025, in numbers it published that August — but that check belongs to v0's deploy path, so if you export to GitHub and host elsewhere it does not come with you.
4. Pages that hand over the whole row
A server‑rendered page can fetch a user or order record and pass the whole object down to a component that runs in the browser. Everything in that object travels with the page, including columns you never display: password hashes, internal flags, other people's email addresses. Nothing looks wrong on screen. Next.js documents this exact pattern as the risk of putting queries straight in a page. Open a page in your browser, view the page source, and search it for a column name that should never leave the server. Then fix it by selecting only the fields the page draws.
5. One gate at the front door
Next.js has a file that can check requests before they reach your pages — middleware.ts, renamed proxy.ts in Next.js 16, where the old name still works but is deprecated. It is the obvious place for an AI to put "protect these routes", and it is a fine first layer. It is a bad only layer: it is normally pointed at a configured list of paths, so anything outside that list is ungated, and this component has had bypass problems — CVE‑2025‑29927, patched in March 2025, let a crafted header skip it entirely. Ask yourself: if this file were deleted tonight, would anything still stop a stranger reading the data? If the answer is no, your login is one file thick.
Before you launch
Work through those five in order — actions, ownership checks, public keys, over‑shared rows, single gate — and you will have covered what the framework does not do for you. Our pre‑launch checklist has the rest, including backups, rate limits and error pages. npx launchprep covers part of this automatically: the free tier is unlimited, runs on your machine and reads without writing, and it catches the exposed‑key class in check 3. The Server Action, ownership, whole‑row and middleware checks need reading the code in context, which is the paid deep scan rather than the free run.
Questions people ask
Does v0 stop me shipping something insecure? Partly. v0 screens what it deploys for exposed secrets and has blocked deployments for it. That catches keys in the wrong place; the checks Vercel describes do not read your permission logic, and they apply to deploys through v0 onto Vercel, not to code you export and host somewhere else.
I never added a database. Am I fine? Largely, and this is the good news of the v0 default. With no database and no login there is much less to take. Check 3 still applies, though — a page with no database of its own can still ship a third‑party API key to the browser. The moment you add a database or a login, all five checks start applying, so run them after the prompt that adds them rather than before.
My app has a login screen. Doesn't that protect everything behind it? No. A login screen decides what gets drawn. It does not decide who may call the functions underneath, and it never decides whether user A may open user B's record. That second check is the one most often missing.