Vercel deployment expert for AI apps — Vercel build fail fix, Vercel env var fix, Next.js deployment fix
A Vercel deployment expert for AI apps fixes the three things that kill 85% of Lovable deploys. We run the Vercel env var fix (diff preview vs production, add Zod preflight), the Vercel build fail fix (tsc + eslint + test gate, Node version pin, output dir), and the Next.js deployment fix (ISR correctness, remotePatterns for images, OAuth redirects, webhook URLs) — fixed price, 48-hour audit, 7-day delivery on the full deploy-to-production pass.
Why AI builders ship broken Vercel deployment
Vercel is the default deploy target for every AI-built Next.js app. AI builders know this, and they generate code that works on Vercel in a single click — right up until you hit a real edge case. The preview URL gets auto-wired env vars, permissive caching, and auto-provisioned domains. Production doesn't. Every assumption in the generated code has to be re-validated on a real domain.
The three failure modes we see, in order of frequency. First, environment variables: the AI builder sets them on preview; you copy them to production and typo one, or forget the NEXT_PUBLIC_ prefix, or put a server secret in the client bundle. Second, edge function timeouts: AI-generated API routes do heavy work inline that exceeds Vercel's 10-second (Hobby) or 15-second (Pro) edge limit; the response never arrives. Third, caching and ISR/static mismatches: a page is statically rendered at build but depends on data that changes per user; it ships stale content or explodes when the user's session doesn't match.
The fourth bucket is smaller but critical: Supabase RLS disabled, OAuth redirects pointing at the preview URL, Stripe webhook endpoints pointing at the preview URL, and image optimization domains not configured. A Vercel deployment expert enumerates every integration, validates every environment, and builds a pre-flight checklist that refuses to deploy if any check fails.
Source: Vercel — Environment variables and edge function limits docs
Which AI builder shipped your broken Vercel deployment?
The Vercel deployment failure mode usually depends on the tool that shipped the code. Find your builder below, then read the matching problem page.
| AI builder | What breaks in Vercel deployment | Go to |
|---|---|---|
| Lovable | Preview env vars never copied to production. OAuth redirects hard-coded to lovable.app. Supabase RLS off. | Lovable deploy fix → |
| Bolt.new | Build config assumes Bolt's runtime. Edge function timeouts on inline Stripe calls. Static pages miss dynamic user data. | Bolt.new deploy fix → |
| v0 | v0 output deploys cleanly; the gap is missing backend. We add API routes and env var wiring. | v0 to production → |
| Cursor | Regression loop — fixes one env var, breaks the next deploy. Caching config drifts across prompts. | Cursor deploy fix → |
| Replit Agent | Code assumes Replit's runtime (long-lived Node process). Vercel's serverless model breaks the cron and background workers. | Replit to Vercel → |
| Claude Code | Writes correct Vercel config when told. Silently assumes localhost env patterns when not. | Claude Code architecture fix → |
| Windsurf | Enterprise CI/CD often bypasses Vercel. Migration to Vercel means rewriting the deploy pipeline. | Windsurf deploy fix → |
| Base44 | Base44 doesn't deploy to Vercel directly. Escape means a full port plus Vercel setup. | Base44 backend fix → |
Anatomy of a 'works in preview, broken in prod' deploy
A Lovable founder messaged us on launch day: 'the preview works perfectly, production is a white screen.' This is the single most-cited pain pattern in our user-needs research — quoted verbatim dozens of times across Reddit, Trustpilot, Medium, and support forums. 'It worked in the preview, broken in production.' 'Won't publish.' 'Won't deploy.' We've rescued more apps from this single failure mode than any other.
The root cause on launch day was a clean example of the top three causes, which combined explain about 85% of Lovable deploy failures. First: environment variables existed in Lovable's preview environment but had never been copied to Vercel production — specifically the Supabase URL, anon key, and a custom email API key. Second: Supabase RLS had been disabled during iteration and never re-enabled; the preview had permissive policies because the AI builder needed them for its own testing, and the production DB had never had explicit policies written. Third: Google OAuth's authorized redirect URIs were still set to the Lovable preview subdomain, so sign-in with Google returned redirect_uri_mismatch and the frontend crashed trying to parse the error response.
“The fix was 4 hours on the emergency triage tier ($299).”
The fix was 4 hours on the emergency triage tier ($299). We ran a scripted diff between preview and production env vars and shipped the missing 7 variables with proper NEXT_PUBLIC_ vs. server-only discipline. We wrote RLS policies for the 11 tables that needed them, tested them from anon and authed roles, and deployed. We added the production domain to Google OAuth's console and Supabase's redirect allowlist. We also installed a pre-flight check as a Vercel build step that refuses to deploy if any expected env var is missing or if a server secret has leaked into a NEXT_PUBLIC_ variable — a 50-line Zod validator that now guards every deploy.
Three months later the founder is on autopilot with the deploy pipeline. The pre-flight has caught two regressions since, both during AI builder re-iterations that tried to add env vars the wrong way. The $299 triage paid for itself before the launch week was over.
What a Vercel deployment rescue engagement ships
From first diagnostic to production handoff — the explicit steps on every Vercel deployment engagement.
- 01
Free rescue diagnostic
Share the repo, the Vercel project URL, and the specific failure (build error, runtime error, or silent regression). In 24 hours we return a written fix plan with a fixed price.
- 02
Deploy audit
We enumerate every env var, every API route, every edge function, every image domain, every webhook URL. We diff preview against production and find the drift. Delivered as a written report.
- 03
Deploy-to-production pass
We fix env var propagation, migrate slow handlers off edge where needed, configure ISR correctly, wire OAuth and Stripe webhooks to the production URL, and add a pre-flight check that refuses broken deploys. $1,999, 7 days.
- 04
Monitoring and rollback
Sentry for errors, Vercel Analytics for Core Web Vitals, Axiom or Logtail for function logs, a documented rollback procedure tested against your staging environment.
- 05
Handoff
Delivery doc, Loom walkthrough of the deploy pipeline, runbook for common Vercel incidents (build failure, function timeout, env var change). Optional retainer for ongoing ops.
Every Vercel deployment rescue audit checks
The diagnostic pass on every Vercel deployment rescue. Each item takes under 10 minutes; together they cover the patterns that cause 90% of AI-built-app failures.
- 01Env var parity between environments
We diff Vercel env vars across Development, Preview, and Production. Missing production entries and preview-only values are flagged.
- 02NEXT_PUBLIC_ prefix discipline
Anything with NEXT_PUBLIC_ ships to every browser. We grep for service role keys, secret keys, and admin credentials in NEXT_PUBLIC_ variables.
- 03Function timeout limits
Vercel Hobby: 10s. Pro: 15s by default, extendable to 60 or 300. Edge: 25s. We audit every API route for inline slow work that risks timing out.
- 04Image optimization remotePatterns
next/image blocks unlisted remote hosts. We map every image source (Supabase, S3, Cloudinary, third-party CDNs) and update next.config.
- 05ISR and static rendering correctness
Static pages with user-specific data are a bug. We identify and either move to dynamic rendering or add proper revalidation.
- 06OAuth redirect URIs in provider consoles
Google, GitHub, Microsoft — every provider's allowlist must include the production URL exactly. Mismatches cause 400s.
- 07Stripe and webhook endpoints pointing at production
Every webhook endpoint must be updated atomically at the cutover; leftover preview URLs drop events silently.
- 08Custom domain and SSL verification
Apex and www variants configured, SSL cert issued, HSTS header set, redirects from non-canonical hosts.
- 09Build command and output directory
Framework preset, Node version, build command, and output directory match what the AI-generated code expects.
- 10Monitoring wired up
Sentry for errors, Vercel Analytics for Core Web Vitals, Axiom/Logtail for function logs. Unmonitored apps fail silently.
- 11Rollback discipline
Every deploy promotable to production via 'Promote to Production'. Reversible migrations so rollback doesn't strand schema changes.
Common Vercel deployment patterns we fix
These are the shapes AI-generated code arrives in — and the shape we leave behind.
01Supabase URL and anon key configured in preview, never copied to production. Production deploy builds but crashes at first page load.01Zod-parsed env module at the top of the app. Deploy fails at build time if any required var is missing. Production and preview env vars managed with a documented diff.01`NEXT_PUBLIC_STRIPE_SECRET_KEY=sk_live_...` in .env. Key ships to every browser.01Server secret named without NEXT_PUBLIC_ prefix. Pre-flight check fails the build if any NEXT_PUBLIC_ variable matches known secret patterns.01API route calls an LLM, waits 12 seconds, times out at Vercel's 10s Hobby limit. User sees 'something went wrong'.01Work enqueued to Inngest, Trigger.dev, or Vercel Cron. Route returns 202 immediately. Client polls or listens via Realtime/webhook.01`/dashboard` marked `export const dynamic = 'force-static'` serves the same HTML to every user. User A sees User B's name.01`dynamic = 'force-dynamic'` or proper ISR with user-specific cache tags. Revalidation on mutation.01Supabase storage URL in `<Image src>` without adding to remotePatterns. Production returns 400 on every image.01next.config.js images.remotePatterns includes every external host. Wildcarded only where necessary; pinned to specific hostnames otherwise.01Stripe webhook endpoint points at the last preview deployment URL. After DNS cutover, every payment event drops silently.01Stripe webhook URL set to the custom domain's /api/webhooks/stripe route. Signing secret rotated. Events replayed via Stripe CLI to verify.01Build command doesn't run tsc or tests. Type errors and regressions ship.01Build command runs tsc --noEmit, eslint, and the unit test suite. Failure fails the build.Vercel deployment red flags in AI-built code
If any of these are true in your repo, the rescue is probably worth more than the rewrite.
Fixed-price Vercel deployment engagements
No hourly meter. Scope agreed up front, written fix plan, delivered on date.
- turnaround
- Free rescue diagnostic
- scope
- Written deploy audit and fix plan in 24 hours.
- turnaround
- Emergency triage
- scope
- Single specific deploy bug fixed in 48 hours with root-cause report.
- turnaround
- Integration fix
- scope
- One integration wired correctly for production — OAuth, Stripe, webhook endpoint.
- turnaround
- Deploy to production
- scope
- Env vars, CI/CD, SSL, monitoring, rollback. 7-day turnaround.
What Vercel deployment rescues actually cost
Anonymized, representative scopes from recent Vercel deployment rescues. Every price is the one we actually quoted.
A founder on launch day with a white screen in production. Env vars, OAuth, RLS are the usual suspects. We triage, fix in hours, ship pre-flight check.
- Scope
- Emergency triage: root-cause identification, three-point fix, pre-flight validator installed.
- Duration
- 48 hours
A seed-stage team whose deploys randomly break features. No monitoring, no rollback discipline, ISR misconfigured.
- Scope
- Full deploy-to-production pass: env parity, monitoring (Sentry + Vercel Analytics), ISR correctness, rollback tested, pre-flight in CI.
- Duration
- 7 days
A growth-stage SaaS migrating off Replit Agent to Vercel. Cron jobs, background workers, and the database need to move cleanly.
- Scope
- Full infrastructure port: Neon + pooling, Inngest for background jobs, Vercel Cron for schedules, staged cutover, monitoring, 2 weeks of stabilization.
- Duration
- 3-4 weeks
Vercel deployment runbook and reference material
The documentation, CLIs, and specs we rely on for every Vercel deploymentengagement. We cite, we don't improvise.
- Vercel — Environment variables
The env var model. Different per environment. NEXT_PUBLIC_ discipline enforced.
- Vercel — Function limits and max-duration
The timeout matrix we reference for every function deployment.
- Vercel — Incremental Static Regeneration
The caching model that AI builders routinely misconfigure.
- Next.js — Image component remotePatterns
The allowlist model for next/image.
- Vercel Cron
Our default scheduler replacement for AI-builder apps.
- Vercel — Rollback and promotion
The rollback path we verify on every engagement.
- Sentry — Next.js integration
Our default error tracker for AI-built Next.js apps.
Vercel deploymentrescues we've shipped
Replit DB swapped for Neon, cron rebuilt on Vercel Cron, hosting cost down 60%.
Added backend, env vars, ISR, and monitoring. Shipped to Vercel Pro in 10 days.
Fixed the preview-to-prod env var gap, OAuth redirects, and Stripe webhooks.
Related Vercel deployment specialists
Most Vercel deployment expert for AI apps engagements start with a Next.js migration off Lovable, Base44, or Replit.
Vercel + Supabase is the common stack. Supabase RLS fix + Vercel env var fix run together.
Vercel webhook endpoints fail silently if Stripe points at preview. Stripe webhook fix re-wires the production URL after the Next.js deployment fix.
Related Vercel deployment problems we rescue
Missing env vars, client/server mismatch, edge runtime gotchas. Vercel env var fix delivered in 2 days.
The full Vercel deploy surface — Vercel env var fix, preview parity, edge runtime, rollback discipline, Next.js deployment fix.
The three fixes that catch 85% of Lovable Vercel build fail fix cases.
Build config, edge function timeouts, and Vercel env var fix propagation.
The regression loop that regresses your Vercel deploy and needs a Next.js deployment fix.
From a beautiful v0 frontend to a real Vercel deployment with backend, env vars, and the Next.js deployment fix applied.
Vercel deployment questions founders ask
Sources cited in this dossier
- Vercel — Environment variables docs
- Vercel — Function timeout and limits
- Vercel — Incremental Static Regeneration
- Next.js — Image component remotePatterns
- Vercel Cron — scheduled functions
- Vercel — Rollback and promotion docs
- Sentry — Next.js integration
- The Register (Feb 2026) — Lovable deployment incident
- Veracode 2025 State of Software Security — AI code
Your AI builder shipped broken Vercel deployment. We ship the fix.
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