r402-aptos

Aptos chain support for the x402 payment protocol, part of the r402 workspace.

Highlights

• Exact scheme — a sender-signed primary_fungible_store::transfer of a fungible asset (USDC by default). The facilitator is the optional feePayer: it verifies the payload, adds its signature, and submits.
• CAIP-2 networks — aptos:1 (mainnet) and aptos:2 (testnet).
• TS payload encoding — outer base64 of UTF-8 JSON { transaction: [u8], senderAuthenticator: [u8] }. Inner bytes are BCS from aptos-sdk 0.6.0 (SimpleTransaction + AccountAuthenticator).
• Gas caps — sponsored txs reject max_gas_amount > 500_000 and gas_unit_price > 1000.
• In-process facilitator — aptos-sdk verify (signature, simulate, FA balance) and settle. Duplicate settle is blocked by SettlementCache keyed by the base64 payload.

Cargo Features

Quick Start (server price tag)

use r402_aptos::{AptosExact, USDC};

let tag = AptosExact::price_tag(pay_to, USDC::aptos_testnet().amount(1_000_000u64));

Documentation

• Crate docs: https://docs.rs/r402-aptos
• Project README: ../../README.md

License

Dual-licensed under MIT and Apache-2.0.