What is HTTP 402 Payment Required?

HTTP 402 is a status code from 1991 signaling payment needed before service. x402 uses it for crypto micropayments, no keys required.

How do AI agents pay with USDC on x402?

Agent hits endpoint, gets 402 with amount. Signs EIP-3009 transfer; server validates gasless via facilitator, then responds.

Maybe for agents—per-task pricing fits autonomy better. But scale and fiat ease keep subs dominant for humans.

🤖 AI & Machine Learning

An AI agent slams into a document analysis API. Server spits back HTTP 402: Payment Required. No keys, no subs—just crypto zap, and it's done.

theAIcatchup Apr 09, 2026 4 min read

HTTP 402 + USDC enables true pay-per-use for AI agents, ditching keys and subs. 𝕏
Live Mac Mini server delivers vision models at $0.01-$0.05 per call, 100% margins. 𝕏
Revives 90s micropayments dream, but crypto UX and scale are the real tests. 𝕏

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Community-driven. Code-first.

#AI agents #HTTP 402 #HTTP 402 #USDC payments #USDC payments #pay-per-use AI APIs #pay-per-use APIs

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Originally reported by Dev.to