@ldclabs/anda_x402

@ldclabs/anda_x402 is the Typescript version of the client SDK for Anda x402 facilitator.

It implements version 2 of the x402 Protocol Specification for the exact scheme on the icp:1 network.

Usage

import { X402Canister, X402_VERSION } from '@ldclabs/anda_x402'

const x402 = new X402Canister('ogkpr-lyaaa-aaaap-an5fq-cai', identity)

// What the facilitator implements, including the `icp:*` signer the payer
// must approve as their ICRC-2 spender.
const supported = await x402.getSupported()

// `paymentRequired` is the server's `PaymentRequired` object, carried by the
// base64-encoded `PAYMENT-REQUIRED` response header over HTTP.
const request = await x402.buildX402RequestFrom(paymentRequired, assetId)

buildX402RequestFrom picks the accepts[] entry to pay:

• Entries for another network or asset, or whose reserved extra keys this SDK does not recognize, are skipped — another entry may still be payable.
• When a resource offers both, authorization wins over upfront, so the funds move only after the resource has delivered.
• Extensions advertised in PaymentRequired are echoed back in the PaymentPayload, as the protocol requires.

The mechanism supports assetTransferMethod: "icrc2" and the authorization (default) and upfront payment flows. escrow is not supported: a single ICRC-2 pull cannot express a deposit settle followed by a final-charge settle.

License

Copyright © 2024-2025 LDC Labs.

Licensed under the MIT License. See LICENSE for details.