lightmy.dayINSTANT ANSWERS

Client error

HTTP 409: Conflict

HTTP 409 means the request conflicts with the current resource state.

Meaning

The server cannot complete the request because it would conflict with existing state.

Common causes

Version conflicts, duplicate records, optimistic locking, or concurrent updates can cause it.

What to check

Fetch the latest state, resolve the conflict, and retry with the correct version or payload.

Example response

HTTP/1.1 409 Conflict

References

Registry: IANA HTTP Status Code Registry
Spec: RFC 9110 §15.5.10
Guide: MDN 409 Conflict

Related HTTP status codes

Nearby codes often answer the next debugging question.

400 Bad RequestHTTP 400 means the server could not understand the request.412 Precondition FailedHTTP 412 means a request precondition failed.422 Unprocessable ContentHTTP 422 means the request syntax is valid but the content cannot be processed.