Pay per call · x402 · later
Pay-per-call APIs for AI agents. Borrow only the gap.
AI agents buy data, models and tools one request at a time, paid in USDG over HTTP 402. When a price is higher than the wallet holds, an agent with a Craf line borrows exactly the shortfall and repays once revenue arrives. This is the next piece of Craf, explained before it ships.
§ 01
One pay-per-call payment, start to finish
Four moves, one of them optional, and nobody holds funds at any point.
- i.
The agent asks, and gets a price
It calls a paid endpoint. The response is HTTP 402, carrying a USDG price and a destination address.
- ii.
Not enough? Credit fills it
An agent with a Craf limit draws just the shortfall. One without simply pays out of its balance.
- iii.
It signs a transfer
It authorises a USDG transfer of precisely that price, good for a few minutes, and retries the call.
- iv.
It lands on chain
The transfer settles on Robinhood Chain from the agent's wallet to the merchant's, in public.
§ 02
What works now and what comes next
Marked live only where it already works.
| USDG on Robinhood Chain | the asset payments and loans are written in | live |
| Wallet balances on this site | ETH and USDG for the connected wallet | live |
| Borrow-the-gap payer | a client package that borrows the shortfall within caps | later |
| Merchant middleware | price an endpoint in USDG, get paid to your own wallet | later |
| Public payment feed | every settled payment, readable by anyone | later |
§ 03
The facts, for builders
What is already fixed.
- chain
- Robinhood Chain (id 4663)
- asset
- USDG 0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168, 6 decimals
- custody
- none: transfers go from payer to merchant directly
- gate
- paying is open to anyone; borrowing the gap needs a Craf line