405 Client Error

405 Method Not Allowed

A 405 Method Not Allowed error means the HTTP method used in the request (GET, POST, PUT, DELETE, etc.) is not supported for the target resource. The server recognizes the method but the resource does not allow it. For developers, this often indicates a mismatch between the client code and the API specification, such as sending a POST to a read-only endpoint.

Common causes

  • Sending a POST request to an endpoint that only accepts GET requests
  • Using PUT or PATCH on a resource that only supports POST for creation
  • Server or framework routing is configured to reject certain HTTP methods on the endpoint
  • A reverse proxy or load balancer is stripping or blocking specific HTTP methods
  • API versioning change removed support for a previously allowed method

How to fix it

  • Check the Allow response header to see which HTTP methods the endpoint supports
  • Review the API documentation to confirm the correct method for the endpoint
  • Update your client code to use the method specified in the API contract
  • Verify reverse proxy and load balancer configurations are not blocking valid methods
  • If building the API, ensure your route definitions explicitly declare all supported methods

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