v0 developer help · Next.js on Vercel
Fix and finish your v0 app.
v0 got the screens right. Now the app needs real data, sign-in, payments and a deploy you can trust. A senior engineer finishes it in your repository, keeping the interface you built.
Photography is illustrative.
- Front end
- Next.js, React, TypeScript, Tailwind CSS and shadcn/ui
- Back end
- None of its own: Neon, Supabase, Upstash or Vercel Blob through the Vercel Marketplace
- Hosting
- Vercel: a preview deployment per branch, production when you publish
- Code
- A GitHub repository as the source of truth, each chat on its own branch and pull request; code export
Who this is for
For founders and teams whose v0 app looks finished and is not yet a product.
v0 (v0.app, called v0.dev until August 2025) builds Next.js apps with React, TypeScript, Tailwind CSS and shadcn/ui, and deploys them to Vercel. It has no back end of its own: databases, storage and sign-in come from services you add through the Vercel Marketplace. Since June 2026, new v0 apps that need a database and sign-in default to Neon, Drizzle and Better Auth.
So a v0 app is often strongest exactly where founders look first, the interface, and thinnest where real users push: data, permissions, payments and environments. That is ordinary Next.js work, which we do every day, and it rarely means touching the screens you are happy with.
Failure modes
The ways v0 apps break.
These are what we look for first in an app built with v0. They sit mostly behind the interface, which is why the app can look done while they are still there.
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Screens with nothing real behind them
- What you see
- Everything looks finished, but data does not save, lists show the same sample rows, or a form submits to nowhere.
- What is actually wrong
- v0 has no back end of its own. Screens generated before a database was connected show sample data, and wiring them to a real one is a separate piece of work.
- How we fix it
- A data model designed for the product, server code that validates every write, and each screen connected to it, keeping the interface as it is.
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Secrets in public variables
- What you see
- An API key turns up in the browser's network tab or page source.
- What is actually wrong
- In Next.js, any variable starting
NEXT_PUBLIC_is sent to the browser, and v0 itself warns against putting sensitive values there. - How we fix it
- Rotate every exposed key, move the calls that need it to server code, and check the built output so nothing secret is left.
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Server actions that do not check who is calling
- What you see
- Nothing visible, until someone changes data they should not be able to.
- What is actually wrong
- A Next.js server action or API route is a public endpoint. If it does not check the user's session and their right to that record inside the function, hiding the button that calls it protects nothing.
- How we fix it
- A session and ownership check inside every action and route that reads or changes data, with a test for each.
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Works in preview, broken in production
- What you see
- The preview deployment works; the published site errors or shows a blank page.
- What is actually wrong
- Vercel sets environment variables per environment (Production, Preview and Development), so a variable added for one is missing in another.
- How we fix it
- A written list of every variable for each environment, a start-up check that fails clearly when one is missing, and a deploy that tests before it goes live.
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Changes that are hard to trace
- What you see
- Nobody can say which chat changed what, and pull requests pile up.
- What is actually wrong
- v0 records a version only when it changes code from a message; editing a file directly creates none. Each chat works on its own branch and opens its own pull request, so parallel chats drift apart.
- How we fix it
- Git as the single record, every pull request reviewed and tested before merging, and one chat per piece of work.
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Payments that unlock on the redirect
- What you see
- Customers get access after closing the checkout page, or keep it after cancelling.
- What is actually wrong
- v0 has had a native Stripe integration since November 2025, but who gets access is still your app's logic. Granting it on the success redirect, instead of on Stripe's confirmed event, is the common mistake.
- How we fix it
- Webhook handling on the server with Stripe's signature verified, subscription state stored and used for access, and the whole lifecycle tested.
Before you hire anyone
What to try yourself first in v0.
- Restore a version. Restoring an earlier version in v0 adds it as the newest version, so nothing is lost by trying.
- Use Fix with v0 on a failed build. On paid plans, fixing a failed deployment is free up to a daily limit for code you have not edited yourself.
- Check every environment variable. In the Vercel project, compare the variables for Production and Preview, and make sure nothing secret starts with
NEXT_PUBLIC_. - Review each chat's pull request. With GitHub connected, read and test each pull request before merging it into the base branch, and use Pull Changes to bring merged work back into a chat.
- Plan the big changes. Use v0's Plan agent to have it lay out a change before it writes code.
- Read the logs. Vercel's build and function logs usually name the failing line. Paste the exact error into v0, rather than the symptom.
How we work
How we work on a v0 app.
v0's documentation says Vercel does not own the code it generates. Once GitHub is connected, the repository is the source of truth: each chat works on its own branch and opens a pull request against the base branch. We work the same way, in branches and pull requests, so you can keep using v0 for interface work.
The app stays on Vercel unless you have a reason to move. Next.js runs on other hosts too, and the databases you added through the Marketplace are accounts in your name.
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A free 20-minute call
You show us the v0 app and tell us what is going wrong. We say what we expect to find, and whether a paid check is worth it yet.
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Quick Security Check or App Readiness Review
A senior engineer reads the code and tests the running app: data access, keys, sign-in, payments, deployment.
You get Every finding in writing with its severity and fix; the review adds a keep, change or replace call for each part and a fixed quote.
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Fixed-price fixes
Security & Data Hardening from $7,500, or Production Launch from $15,000, in your repository, with a test beside each fix.
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Handover
Production kept apart from development, a deploy you can roll back, and notes so you, the tool or any developer can carry on.
Prices
Where to start, and what it costs.
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App triage call
Free
20 minutes
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Quick Security Check
$495
Delivered in 48 hours. The fee is credited toward the App Readiness Review.
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App Readiness Review
$1,500 flat
5 business days. The fee is credited toward any fix booked within 30 days.
Fixes are priced after the check or review, at one fixed price before anything starts. The full price list and how fees are credited.
Proof
Who does the work.
A US software engineering firm. The founding team has taken a product off an AI app builder before (built, not yet in paid use) and runs a production telehealth platform on Supabase. We are an independent firm, not a v0 partner or agency. Across the systems the team built and runs:
- 20,900+ automated tests across the systems the founding team built and runs
- 16,800+ CI runs automated builds and test runs on GitHub Actions
- 940+ merged pull requests across the same codebases
Counted from the repositories and CI history of the systems the founding team built and runs, 22 Sep 2026; each figure rounded down. How we counted
Questions buyers ask
v0 questions, answered.
Can I keep designing in v0 after you add the back end?
Yes. We merge into the base branch through reviewed pull requests, and Pull Changes brings that work into your v0 chats, so you can keep shaping the interface.
Does my v0 app need a back end?
If it stores data, has users or takes payments, yes. v0 adds one through Marketplace services such as Neon or Supabase; making it correct and secure is the part we do.
Do I have to stay on Vercel?
No, but most v0 apps are well served there. We recommend staying or moving after the review, with the reason.
Will you redo the design?
No. The interface is usually the best part of a v0 app. We work behind it, and change screens only where a fix needs it.
Are you affiliated with Vercel?
No. Oracis is an independent US software engineering firm. We fix and finish apps built with v0, alongside apps from Lovable, Bolt, Replit and other tools.
What does it cost to fix a v0 app?
The first call is free. The Quick Security Check is $495 and its fee is credited toward the App Readiness Review, which is $1,500 flat and credited toward any fix booked within 30 days. Security & Data Hardening is from $7,500 and Production Launch from $15,000, each at one fixed price set after the review. We never bill hourly on work nobody has sized. The full price list.
Send us the v0 app.
The v0 chat or the GitHub repository, what the app needs to do, and when it needs to be live.