HTTP 402: The Payment Code That Sat Empty for 28 Years — And Why AI Agents Just Activated It

HTTP 402 was reserved in 1997. Browsers implemented 404. They implemented 500, 401, 403. They implemented dozens of status codes. 402 — "Payment Required" — sat empty for 28 years. Last month, $24 million moved through it. Here's why that matters for anyone building AI agents. The Original Vision Tim Berners-Lee wanted the web to have a native payment layer. When he defined HTTP status codes, 402 was the placeholder for a future where web resources could charge for access natively — no third-party checkout pages, no OAuth flows, no redirect dances. It never shipped. For nearly three decades, online payments were handled by bolted-on infrastructure: card rails, payment processors, checkout flows designed around a human who sits at a keyboard and clicks a button. That assumption — a human authorizes each transaction — was baked into everything. Why AI Agents Changed This AI agents exposed the gap. Agents make decisions at machine speed. They're calling APIs, accessing resources, completi