HTTP 402 Was 'Reserved for Future Use' for 29 Years. Stripe Just Gave It a Job.

HTTP 402 has been "reserved for future use" since 1997. Stripe just gave it a job. The HTTP spec defined 402 Payment Required almost 30 years ago. Nobody knew what to do with it. Some APIs used it for failed card charges. Most developers forgot it existed. Then Stripe launched the Machine Payments Protocol this week. And suddenly, 402 is doing exactly what it was designed for. Here's what happened Stripe and Tempo co-authored MPP as an open standard for machine-to-machine payments. The idea is simple. When an AI agent requests a paid resource, the server returns HTTP 402 with payment details. The agent pays. The server delivers the resource. No account creation. No pricing page. No checkout flow. Just a status code, a payment, and access. That might sound boring on paper. But think about what it replaces. Right now, if your agent needs to call a paid API, someone has to manually sign up, enter a credit card, pick a subscription tier, and paste in the key. MPP skips all of that. The pro