A pay-per-call endpoint has no account to sign up for and no key to carry. The price travels in the 402 response, the payment travels in the retry, and the two are bound together by a single-use authorization, so the same signature can never be charged twice.
This is the same handshake an AI agent performs. The difference is that the wallet shows you the quote before anything is signed, in the token and on the network the endpoint named, so the authorization you approve is the one that settles.
Pay an endpoint
- 1
Open Send and paste the endpoint's https URL into the recipient field, or tap Scan and point the camera at the URL's QR code.
- 2
Read the quote: the price in USDC, the network it settles on, and a preview of the resource when the seller provides one.
If the endpoint quotes a network you hold no USDC on, the app tells you which one before you can approve anything.
- 3
Approve on your device. The screen lists every field being signed: recipient, amount, network and expiry.
Nothing is transmitted until you approve, and the authorization expires on its own if you walk away.
- 4
Read the response in the app. It is kept in your purchase history, so a response that arrived while the app was in the background is not lost.
Good to know
- Payments use the same USDC balance as any send. Spending guardrails apply: a daily cap or an allow-list that would block a send blocks an x402 payment too.
- The endpoint's price is what you pay. The app adds no fee of its own on the buyer side; the seller's own service fee, if any, is theirs.
- Ask Copilot what an endpoint costs before paying. It reads the 402 quote without spending anything and offers the pay screen with the URL filled in.
Frequently asked
Whatever the endpoint quotes and you hold USDC on. Most x402 endpoints today quote Base; Polygon, Arbitrum and Solana are also common. The quote screen names the network.
The authorization is time-limited and single-use, so an endpoint that does not settle it cannot charge you later. A settled payment whose response was lost in transit is recoverable from your purchase history, which stores the response body.
No. x402's exact scheme relies on USDC's transfer-with-authorization feature, which USDT does not implement.
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