Types of API Changes

Breaking Changes

Adding a new required field in the request body of an existing endpoint
Adding a new update-able field to response
Renaming an existing field in the request body of an existing endpoint
Renaming an API endpoint (changing the URL structure)
Removing an API endpoint
Removing a field from the request or response body of an existing endpoint
Remove a query parameter from an existing endpoint
Changing the value type of an existing field in the request body of an existing endpoint. (Eg: from integer to string)
Modifying the allowed values of an enum field
Converting an optional field in the request body of an existing endpoint to required
Adding/Modifying validation to an existing field of an existing endpoint
Modifying existing response error codes, response error messages
Modifying existing fields (keys/value types) of the response body
Changing the response status code (Eg: HTTP 200 to 202)
A significant change in functionality of an existing endpoint that results in surprising new behavior