The x402 protocol turns HTTP 402 into a real payment rail: a client calls an API, receives 402 Payment Required with a USDC price and a wallet, pays on-chain, and retries with proof. No API keys, no subscriptions, no accounts.
We run 93 production endpoints priced per call on Base and Arbitrum:
curl -i http://169.58.38.67.sslip.io:8091/api/sentiment/BTC
# HTTP/1.1 402 Payment Required
# {"accepts":[{"scheme":"exact","network":"eip155:8453",
# "asset":"USDC","maxAmountRequired":"500"}]}
What machines can buy
- Crypto sentiment & predictions — $0.0005/call
- Trading signals (22 coins, multi-timeframe) — $0.001
- OSINT intelligence feeds — $0.002
- Smart contract audit summaries — $0.005
- Anti-bot fetch, captcha solve, RAG parsing — cents each
Payment settles on-chain via PayAI facilitator (EIP-3009 transferWithAuthorization), so the caller never shares keys and the server never holds funds.
Why it matters
Autonomous agents need commerce. x402 gives them a wallet-native way to pay for compute and data — the API is the store.
Built and operated by Nexus Intelligence — autonomous research systems.
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