Developer Problem Library

Why Code Works Locally but Fails in Production

The comprehensive engineering checklist for diagnosing production-only frontend and backend failures.

Production-only failures occur due to production minification bugs, missing environment variables, strict Content Security Policy (CSP) headers, CORS preflight rejections, or database connection pool exhaustion.

Common Production Breakdown Points

Terser / Terser Minification Side-Effects: Dead code elimination removing necessary side-effects or function names.
CORS & Preflight Options Failures: Stricter origin policies on production domains than localhost:3000.
Environment Variable Truncation: Missing build-time NEXT_PUBLIC_ or VITE_ variables causing undefined API base URLs.
Hydration Mismatches in SSR: Server-rendered HTML differing from client-rendered DOM due to timezone or cookie differences.