Error categories
Pick a technology to see its most common errors, or paste your error and let us figure it out.
HTTP
HTTP status codes from 400 Bad Request to 504 Gateway Timeout — what they mean and how to fix them on any server.
30
API
REST/GraphQL API errors: invalid tokens, CORS, rate limits, timeouts and malformed requests.
9
Authentication
Login, session, JWT and OAuth 2.0 / OpenID Connect errors.
5
JavaScript
Browser and runtime JavaScript errors: TypeError, ReferenceError, SyntaxError and promise rejections.
50
PHP
PHP fatal errors, warnings, parse errors and configuration limits.
50
Python
Python exceptions: ImportError, KeyError, TypeError, IndentationError and more.
53
Java
Java and JVM exceptions: NullPointerException, ClassNotFoundException, OutOfMemoryError.
50
SQL
Database-agnostic SQL errors: syntax, constraints, deadlocks and connection issues.
51
MySQL
MySQL and MariaDB error codes like 1045, 1064, 1146 and 2002.
50
PostgreSQL
PostgreSQL connection, authentication and query errors.
53
Git
Git and GitHub errors: rejected pushes, merge conflicts, SSH keys and unrelated histories.
51
npm
npm install and dependency errors: ERESOLVE, EACCES, lockfile and registry problems.
50
Node.js
Node.js runtime errors: module resolution, ports in use, file system and network errno codes.
52
React
React runtime and build errors: invalid children, infinite re-renders, hooks and keys.
51
Android
Android, Gradle and ADB build/install errors.
6
iOS
Xcode, Swift, CocoaPods and code-signing errors.
6
Docker
Docker daemon, image, container, port and disk errors.
7
Kubernetes
Pod states and cluster errors: CrashLoopBackOff, ImagePullBackOff, OOMKilled.
7
AWS
Amazon Web Services errors: IAM AccessDenied, expired tokens, throttling and S3 issues.
7
Azure
Microsoft Azure authentication (AADSTS) and deployment errors.
6
Linux
Linux shell, permission and package-manager errors.
7
Windows
Windows system error codes and stop codes.
10
.NET
.NET runtime and ASP.NET Core exceptions.
6
Cloudflare
Cloudflare 5xx errors (520–526) between the edge and your origin server.
7
WordPress
WordPress database, plugin, theme and server errors.
6