Next.js Build Error Decoder
Paste the raw output of a failing next build or a stuck next dev. The decoder matches 14 real failure signatures, points at the line that gave it away, and gives you the fix. Nothing you paste leaves your browser.
Paste the whole thing — the failing line is usually a few lines above the stack trace. Results update as you type.
Or load a real error
Diagnosis
Paste your output, or load a real error. For each of the 14 failures it knows, the decoder gives you:
- 1The line that gave it awayquoted from your own output, with its line number
- 2Why it happensthe mechanism, not just the message
- 3The fixa snippet to apply, and the deep-dive with every variant
Errors this decoder recognizes
Each signature comes from an error we have hit and documented — the diagnosis links to the deep-dive with reproduction steps and every variant of the fix.
useSearchParams() should be wrapped in a suspense boundaryread the fix →ChunkLoadError: Loading chunk failedread the fix →Dynamic server usage: couldn't be rendered staticallyread the fix →window is not definedread the fix →Module not found: Can't resolve …read the fix →Can't resolve '@/…' (path alias)read the fix →JavaScript heap out of memoryread the fix →Hydration failed / text content does not matchread the fix →Dev server stuck on "compiling…"read the fix →EADDRINUSE: port 3000 already in useread the fix →process.env.X is undefinedread the fix →Cannot find module 'next/babel'read the fix →next/image hostname not configuredread the fix →next lint removed (Next.js 16)read the fix →Build passes but production is broken?
A green build is not a working app. Check your env variables with the Env Leak Checker and read the postmortem of a build that passed while production silently broke.
Read the postmortemStep-by-step fixes for these errors
This tool runs on dev-error-explainers, an open-source, zero-dependency library — view the source on GitHub.