Part 3/12:
The protocol is inspired by the HTTP 402 status code, which indicates a payment is required. When a user or AI agent makes a request to a paywall-protected resource, the server responds with a 402 message detailing the price and payment instructions. The payer then deposits the specified amount, and upon confirmation, the request is retried, granting access. This seamless process enables small, instant payments without complicated account setups.