application/*
application/x-www-form-urlencoded
Classic HTML form submission — key=value&key=value pairs.
What is application/x-www-form-urlencoded?
application/x-www-form-urlencoded is the default Content-Type sent by HTML <form method="POST"> submissions. Fields are encoded as key=value pairs joined by ampersands, with special characters percent-encoded.
Typical usage
Traditional HTML form POST, OAuth 2.0 token requests, many legacy APIs.
Common gotchas
Cannot represent binary data or nested structures cleanly. For file uploads use multipart/form-data; for structured payloads use application/json.
HTTP header example
Response header
Content-Type: application/x-www-form-urlencoded; charset=utf-8Reference
HTML Living Standard §4.10.21.7