x402

Python SDK for the x402 payment protocol — supports TRON and EVM (BSC) networks.

Current release: bankofai-x402==0.6.1. This release fixes TRON exact_permit facilitator settlement through wallet CLI backed signers and remains aligned with the TypeScript SDK for client, server, and facilitator exact, exact_permit, and exact_gasfree flows.

Compatibility Notes

• The EVM exact flow is being aligned to the Coinbase x402 v2 payload shape.
• Exact transfer authorizations are represented in payload.authorization.
• Server-side migration fallback still accepts the legacy extensions.transferAuthorization field while the spec-aligned path becomes primary.

Installation

pip install bankofai-x402==0.6.1

Optional extras:

pip install "bankofai-x402[tron]"
pip install "bankofai-x402[fastapi]"
pip install "bankofai-x402[flask]"
pip install "bankofai-x402[all]"

Quick Start

from bankofai.x402.clients import X402Client

client = X402Client()

If you want automatic handling of HTTP 402 responses, use X402HttpClient:

import httpx

from bankofai.x402.clients import X402Client, X402HttpClient

x402_client = X402Client()
http_client = httpx.AsyncClient()
client = X402HttpClient(http_client=http_client, x402_client=x402_client)

BSC Testnet Example

For a complete BSC testnet exact smoke example, including a local-private-key client and a server that advertises DHLU for ERC-3009, see examples/bsc-testnet-smoke/README.md.

The key point for BSC exact is that the advertised asset must actually support transferWithAuthorization. The smoke-tested path in this repository uses DHLU on eip155:97.

Supported Schemes

• exact_permit: Standard x402 payment scheme using TIP-712/EIP-712 permits.
• exact_gasfree: (TRON) Pay with USDT/USDD without TRX gas using the GasFree protocol.
• exact: (EVM) Native direct payment using ERC-3009.

Links

• Repository: https://github.com/BofAI/x402
• Issues: https://github.com/BofAI/x402/issues
• Documentation: https://docs.bankofai.io/
• Contributing: CONTRIBUTING.md