> ## Documentation Index
> Fetch the complete documentation index at: https://docs.autolayer.fi/llms.txt
> Use this file to discover all available pages before exploring further.

# x402 Facilitator

> Verify and settle exact SEP-41 payments on Stellar testnet and mainnet.

AutoLayer composes the upstream Apache-2.0 `@x402/stellar` exact facilitator for `stellar:testnet` and `stellar:pubnet`. The buyer signs a Soroban authorization entry permitting a specific token transfer. The facilitator builds, simulates, submits, fee-sponsors, and confirms the invocation without taking custody of buyer funds.

## Wire flow

1. A protected server returns HTTP `402` and a `PAYMENT-REQUIRED` header.
2. The buyer validates network, asset, amount, recipient and expiry.
3. A SEP-43-capable wallet signs the Soroban authorization entry.
4. The buyer retries with `PAYMENT-SIGNATURE`.
5. The resource server or gateway calls `/verify`, then `/settle`.
6. Successful delivery includes `PAYMENT-RESPONSE` with the settlement receipt.

`GET /supported` advertises x402 v2 exact support, CAIP-2 identifiers, facilitator signers, discovery extensions, and `extra.areFeesSponsored: true`.

## Assets and precision

Settlement accepts SEP-41 token contracts. USDC is the default configured asset, but the verifier uses the payment requirement’s explicit contract. Amounts are integer base units; Stellar assets commonly use seven decimal places. Recipients of issued Classic assets need the appropriate trustline, while contract recipients follow the token contract’s rules.

## Failure rules

Every rejection contains a non-null reason. Modified asset, amount, payee, invocation, expiration or signature must fail. Verification never transfers funds. Failed verification or settlement never falls through to protected resource delivery.

<Warning>`exact` is advertised. `upto` remains unadvertised until the Stellar scheme document, recipient-bound settlement implementation, upstream contribution, conformance fixtures and security review are complete.</Warning>