What is the difference between 413 and 415 errors?

While both relate to request content issues, they are distinct. A 413 (Request Entity Too Large) indicates the request body is too large. A 415 (Unsupported Media Type) signifies that the server doesn't accept the format of the data being sent (e.g., trying to upload a file with the wrong extension when the server only accepts JSON). The size is the primary issue for 413, while the media type is the primary issue for 415.