It is part of the HTTP/1.1 protocol defined by the Internet Engineering Task Force (IETF) in the RFC 7231[1] specification.
It provides a clear indication to the client that they need to take action to complete the payment process before they can access the requested resource.
Client request: Server response:[3] The HTTP 402 status code is typically used in e-commerce and subscription-based systems where access to content or services is restricted until the user completes a payment.
Web developers and institutions are advised to adhere to recognized HTTP norms and employ stable, thoroughly documented status codes.
[6] The server may also include relevant headers in the response, such as Retry-After, which indicates the time duration the client should wait before retrying the request after completing the payment process.