Topic
Next.js & React in Production
`next dev` is green, `next build` fails; the page is 200 locally and 500 on Vercel. This cluster is about the gap between development and production in Next.js: undefined env variables, DYNAMIC_SERVER_USAGE from a nested server component, and Turbopack crashing on exactly one machine. For App Router developers whose bugs only appear after deploy.
8 articles
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Next.js Environment Variable Undefined in Production? Here's Why
Cmd+K Search Returns "No matches" for Almost Every Keyword in Prod? The Index Was Built From Placeholders
July 11, 2026
Production Serving Stale HTML After a Deploy? A `Cannot read properties of undefined (reading 'toFixed')` Was Crashing SSR
July 10, 2026
Article Page Is 200 in `pnpm dev` but 500 in Production? `DYNAMIC_SERVER_USAGE` From a Nested Server-Component Fetch
July 9, 2026
Sanity Panel 500s in Prod, API Returns 400 `score() function received unexpected expression`? boost() Only Takes Simple Predicates
July 9, 2026
`next dev` Is Green but `next build` Fails Type-Check: Dynamic Element With `ref` and `children` Typed `never`
July 8, 2026
Next.js 16 Works on `localhost` but HMR Dies Over a LAN IP? Add `allowedDevOrigins`
July 8, 2026
`next dev` Turbopack Crashes With `invariant expected layout router to be mounted` on One Machine Only? A `node_modules` Junction Is the Culprit
July 8, 2026