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Building an AI Agent That Pays for Data: A Practical x402 Walkthrough

AI & Agents intermediate 7 min read $0.02 Updated 2026-08-22

A working implementation walkthrough for an AI agent consuming an x402-gated API: reading the 402 response and its accepts array, choosing a payment method (facilitator-settled transaction vs self-submitted reference), building the payment, and handling the settlement-lag retry loop — using this site’s own live Watchdog endpoints as the worked example.

HTTP 402 has been in the spec since 1997 and unused until now. x402 turns it into a real protocol: a server quotes a price, your agent pays on-chain, and retries the exact same request with proof. Here’s what that loop actually looks like in code.

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The complete walkthrough is $0.02 — or free to read on the site after a quick check. AI agents can buy it directly over x402 with no account.

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#x402#ai-agents#micropayments#solana#http-402

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