HTTP 409 Conflict

In short: The request conflicts with the current state of the resource.

In more detail: The request is formally fine but cannot be executed right now: for example because another change came in between or the entry already exists. The body usually explains how to resolve the conflict.

In Depth

When it occurs

• Registration with an e-mail address that already exists.
• Two people edit the same resource at the same time (version conflict).
• Deleting a folder that still has content.

What you can do

1. Reload the current state and try the change again.
2. Choose different input (another name, another address).
3. Developers: send a version number or ETag and explain the conflict clearly.

See also: HTTP Status Codes Overview, HTTP