Ask once. Watch it pay.

A live, OpenAI-compatible router on Robinhood Chain. Everyone gets 5 free questions a day. After that each one is a real 0.005 USDG payment: you sign, Farebox pays the gas, and the exchange panel fills in as it happens.

POST /api/v1/chatfarebox-router
Paying needs a wallet with a little USDG on Robinhood Chain, and a little ETH once for the Permit2 approval. The free allowance needs nothing.
  1. RequestPOST /api/v1/chat
    Your message goes to the router as a normal chat-completion request.
  2. Price402 Payment Required
    Without payment the router answers with the exact amount, asset, recipient and window.
  3. SignPAYMENT-SIGNATURE
    Your wallet signs a Permit2 transfer. No gas and nothing on-chain yet, after a one-time approval.
  4. Verify & settle/verify → /settle
    verify…
    settle…
    Farebox checks the signature, simulates the transfer, then broadcasts it on Robinhood Chain and pays the gas.
  5. Delivered200 OK
    The completion, with the settlement receipt in a header.

Or fund a key your agent spends.

Pay once in USDG and the key carries that balance. Your agent calls Farebox like any OpenAI-compatible API with Authorization: Bearer, and each request is debited 0.005 USDG. No wallet inside the agent.

Funding uses the same 402 → sign → settle flow as a request.

Or skip the browser.

curl · free allowance
curl …/api/v1/chat \
  -H 'Farebox-Free: 1' -H 'content-type: application/json' \
  -d '{"messages":[{"role":"user","content":"hi"}]}'
# 200 with Farebox-Free-Remaining: 4 … then 402 once spent
headless agent · pays per request
AGENT_PRIVATE_KEY=0x… npm run agent -- chat "hi"
# @x402/fetch handles 402 → sign → retry; prints the reply and the receipt