Stop Debugging Blindly

401 Unauthorized Error

Your API returns 401 Unauthorized, meaning the server doesn't recognize your credentials or your token has expired.

403 Forbidden Error

You're authenticated (logged in) but the server denies access because you lack the required permissions or role.

JWT Token Expired

Your JWT access token has passed its expiration time (exp claim), causing API requests to fail.

Session Not Persisting

User sessions aren't being saved between page loads, causing users to be logged out on every refresh.

API & Network

CORS Error on Localhost

Your browser blocks requests from localhost to your API because of Cross-Origin Resource Sharing (CORS) policy restrictions.

critical

500 Internal Server Error

The server encountered an unexpected error and couldn't process your request.

Network Request Stuck Pending

Network requests start but never complete, leaving the UI in a loading state indefinitely.

JSON Parse Error

Your code expects JSON but receives malformed or non-JSON data, causing parse errors.

State Management

React State Not Updating

You call setState but the component doesn't re-render or the UI doesn't update to show the new value.

useEffect Infinite Loop

Your useEffect runs repeatedly, causing infinite re-renders and crashing the page.

Performance

Slow Initial Page Load

Your page takes too long to display content, hurting user experience and SEO.

Memory Leak Detected

Your application's memory usage grows over time, eventually causing slowdowns or crashes.

Build & Deploy

Module Not Found Error

Your bundler can't find a module you're trying to import, causing build failures.

critical

Build Out of Memory

Node.js runs out of memory during the build process, causing it to crash.

CSS Styles Not Loading

Your CSS works in development but styles are missing or broken in production.

Environment Variable Undefined

Environment variables are undefined in your application, causing features to break.

Webpack Chunk Loading Error

Users get 'Loading chunk failed' errors after you deploy a new version.

Browser & DOM

localStorage Not Available

localStorage is undefined during server-side rendering or blocked in private browsing mode.

Framework-Specific

React Hydration Mismatch

React's hydration process fails because the server-rendered HTML doesn't match what the client tries to render.

Next.js Image Optimization Error

The Next.js Image component throws errors about unconfigured hostnames or missing dimensions.

Next.js API Route Not Working

Your Next.js API route returns 404 or doesn't handle requests correctly.