HTTP 402 Payment Required: The Dormant Status Code That Powers the Agent Economy

Every web developer knows 200 OK, 404 Not Found, and 401 Unauthorized. But there's a status code that has been sitting in the HTTP specification since 1997, doing essentially nothing: 402 Payment Required. The original HTTP/1.1 spec (RFC 2068) defined 402 as "reserved for future use." The authors knew that the web would eventually need a native way to say "this resource costs money — pay first, then access." They just didn't know how digital payments would work yet. Credit cards weren't built for sub-cent transactions. PayPal didn't exist. Bitcoin was a decade away. Twenty-nine years later, three things have converged to make 402 not just useful, but essential: AI agents that consume APIs autonomously, Lightning Network micropayments that settle in milliseconds, and macaroon tokens that embed payment proofs with capability constraints. Together, they form the L402 protocol — and it turns HTTP 402 from a placeholder into infrastructure. What HTTP 402 Actually Means HTTP status codes com