HTTP Status Codes and Headers Quick Reference
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A practical reference for API response codes, caching, retries, authentication and request tracing.
Quick reference#
| Task or concept | Command or value | Operational note |
|---|---|---|
| Successful read | 200 OK | Return the representation. |
| Created resource | 201 Created | Include a Location header. |
| Invalid input | 400 Bad Request | Return field-level details. |
| Unauthenticated | 401 Unauthorized | Send an authentication challenge when applicable. |
| Forbidden | 403 Forbidden | Identity is known but not allowed. |
| Missing resource | 404 Not Found | Avoid leaking private-resource existence. |
| Conflict | 409 Conflict | State conflicts with the operation. |
| Rate limited | 429 Too Many Requests | Include Retry-After. |
| Temporary failure | 503 Service Unavailable | Retry only when the operation is safe. |
How to use this page#
Find the task first, copy only the relevant value, replace placeholders, and confirm the target environment before running anything.
Safety rules#
- Prefer read-only inspection before mutation.
- Use least-privilege credentials.
- Keep secrets out of commands, logs and screenshots.
- Test state-changing operations in a safe environment.
- Capture the original value and rollback path.
Placeholder conventions#
NAME,UNIT,PATHandURLmust be replaced.- Ellipses indicate omitted application-specific content.
- Quotes are part of a command only when shown inside the code element.
Incident-use checklist#
- Record account, host, region or environment.
- Record the current time and relevant request identifier.
- Run the narrowest read-only command.
- Save useful output without sensitive data.
- Escalate before destructive or irreversible changes.
Version note#
Commands and APIs can change. Verify behavior against the official source below and the exact runtime version in use.
