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Next.js Site Broke After Deploy or Release

Use this page if deployment completed successfully, the app still works locally, but the live site broke after the release and the failure only shows up against production data, config, runtime behaviour, or traffic.

Stabilise a Next.js production incident after deploy when the app works locally but the live site is now broken, inconsistent, or only failing against production conditions.

Typical symptoms

  • The deploy succeeded, but the live site started returning errors, missing content, or broken UI immediately afterwards.
  • The problem reproduces only in production or only against live data and configuration.
  • Teams are deciding between rollback and patching without a trusted diagnosis of what changed.

Likely causes

  • Production runtime configuration, environment variables, or external dependencies differ from local assumptions.
  • The release changed route, middleware, caching, or rendering behaviour in ways that only show up in the live environment.
  • The platform has one production‑only boundary failing, but logs and symptoms make it look broader than it is.

What I look at first

  • Quick check: reproduce one failing production route end to end and capture the first point where the live behaviour diverges from the expected release path.
  • Whether the breakage is route‑specific, shared‑layout, middleware, auth, or data‑source related.
  • What changed in the release across dependencies, environment config, and runtime assumptions.

How I help fix this

  • Reduce the incident to the production boundary that is actually failing.
  • Prioritise containment, rollback, or forward‑fix options against the real live risk.
  • Support implementation changes that stabilise the site without creating a second production surprise.

When to bring me in

  • Bring me in when the release succeeded technically but the live site is now broken enough to affect customers, editors, or revenue.
  • Bring me in when the issue only reproduces in production and each attempted fix is increasing risk rather than reducing it.

Related project experience

  1. Linkudo

    Freelance full‑stack developer for this modern reimagining of the classic browser‑based word association game. Built with Next.js, Node.js, Supabase, and Redis.

    Screenshot of the Linkudo website; part of John Kavanagh's development portfolio.

  2. Nando’s

    Senior software engineer on the UK and Ireland replatform, migrating Nando’s customer‑facing websites from legacy Drupal to a unified headless platform built with Next.js and Storyblok, with a focus on performance, accessibility, and SEO.

    Screenshot of the Nando’s website; part of John Kavanagh's development portfolio.

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Questions teams usually ask

How is this different from build failure debugging?
This page is for releases that already deployed. The problem is not getting the build through CI, but explaining why the live site broke afterwards under real production conditions.
Can you help if we cannot reproduce it locally?
Yes. Production-only failures are common. The job is to narrow the incident to the first real production boundary that is failing rather than waiting for a perfect local reproduction before acting.

Tell me what needs fixing

Send me the affected page or route, point me at the code if that helps, and tell me what you expected to happen versus what is happening now. If this connects to a Next.js migration, technical SEO drop, performance issue, launch, or platform move, include that context too. I'll come back with the clearest next step.

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