Pay APIs from your AI agent in 30 seconds.

HTTP that finally pays itself.

Every API on the market today assumes a human registers, files a card, and watches a dashboard. Your agent doesn't. HTTP 402 is the wire protocol that gives APIs a way to charge per call without a human in the loop. USDC on Base settles atomically in ~1.2 s. Five lines of curl plus a transaction is the whole client.

Five lines of curl + USDC.transfer() is the minimum viable client. No SDK is mandatory. The wire protocol is the contract.

From zero to 200 OK.

# 1 — quote
curl -i -X POST https://api.tools402.dev/v1/pdf-md \
     -F "file=@receipt.pdf"

HTTP/1.1 402 Payment Required
{ "maxAmountRequired": "10000", "payTo": "0xD6E8…2878" }

# 2 — pay on Base
cast send 0x833589fCD…2913 \
     "transfer(address,uint256)" \
     0xD6E8…2878 10000 \
     --rpc-url https://mainnet.base.org

✓ tx 0x4f02… · 1 confirm · ~1.2 s

# 3 — retry
curl -X POST https://api.tools402.dev/v1/pdf-md \
     -H 'X-Payment: eyJ4NDAyVi…ifQ' \
     -F "file=@receipt.pdf"

HTTP/1.1 200 OK
{ "markdown": "# Receipt …" }

Drop into the runtime your agent already speaks.

Same wire protocol behind each. Each official package handles 402 → pay → retry, signing, idempotent retries, and 60-second timeout recovery.

How much does your agent cost to run?

Slide the knobs. The number on the right is what you'd pay per month, settled atomically on Base. Compare against a typical Twilio + Clearbit + GPT API setup.

Never goes silent.

When Coinbase facilitators went silent for 25 days in January 2026, we didn't. Multiple x402 facilitators run in parallel — Coinbase CDP / PayAI / local-key signer per chain — with sub-500 ms automatic failover. Buyer payment is live on Base, Polygon, and Solana. See /proof for the live runtime list.

Our proprietary routing engine — 105 tests, 100 % coverage, battle-tested in production — is the operational moat.

Common questions.