402 Payment Required
Meaning
Reserved for future use. Intended for cases where payment is required for access, but no standard use currently exists.
When to Use
Rarely used in practice. Could be used in experimental or proprietary APIs to indicate the client needs to pay (or has exceeded a quota) before the request can be fulfilled.
Example
Some APIs might return 402 Payment Required if a user has exceeded a usage quota or needs to upgrade their plan (though 402 is not widely adopted).
When Not to Use
Do not use for general unsuccessful requests. Since there's no official standard implementation for 402, it's usually avoided or repurposed in limited cases.
Source
RFC 9110