409 Conflict

What it means

Common in APIs when creating a duplicate record or updating something that changed since it was read.

Common causes

• A duplicate unique value, such as an existing username.
• An edit conflict with a newer version.

How to fix it

1. Fetch the latest version and retry.
2. Choose a different unique value.

Example response

HTTP/1.1 409 Conflict
Content-Type: application/problem+json

Worked example

A client sends a request the server cannot fulfill as submitted. Check the response body and request details, correct the input or permissions, and retry only after the relevant issue is resolved.

How to read this response

1. Find the status line in your browser's Network panel, API client, or server access log.
2. Read the response body and headers shown above; headers such as Location, Allow, Retry-After, and WWW-Authenticate explain the next step.
3. Use the code's class to orient your diagnosis: informational, successful, redirected, request-related, or server-side.

How to check a status code

Enter a URL in the HTTP Status Checker to see its status code, every redirect hop, and response time. For redirect-heavy pages, the Website Speed Test shows how much time redirects add.

Frequently asked questions

What it means: HTTP 409

409 Conflict: The request conflicts with the current state of the resource.

Common causes: 409

A duplicate unique value, such as an existing username. An edit conflict with a newer version.

How to fix it: HTTP 409

Fetch the latest version and retry. Choose a different unique value.

Tools