Convention for HTTP response header to notify clients of deprecated API
I'm upgrading our REST API endpoints and I want to notify clients when they are calling the to-be-deprecated endpoint. What header should I use in the response with a message along the lines of "This API version is being deprecated, please consult the latest documentation to update your endpoints" I would not change anything in the status code to be backward compatible. I would add a "Warning" header in the response : Warning: 299 - "Deprecated API" You can also specify the "-" with the "Agent" that emits the warning, and be more explicit in the warn-text : Warning: 299 api.blazingFrog.com