This project is forked from x402-rs in Oct 2025. The source code is released under the same Apache 2.0 license.

The x402 facilitator project aims to create universal x402 payment infrastructure for both humans and machines (AI agents). It will support the x402 payment protocol across

• all blockchains.
• all fungible tokens and coins, including all ERC-20 compatible tokens.
• traditional credit card payment networks.
• traditional bank transfers.

The initial focus is to support USDC and USDT stablecoins across blockchains.

• Rust crate for x402-facilitator
• Documentation
• Demo: payment link | screencast

The x402-facilitator works with all x402-compatible clients, SDKs, and middleware. Just configure them to use your own facilitator server (see below).

• RECOMMENDED: x402 payment link similiar to Stripe payment links
• The Coinbase SDKs for Python and Typescript
• Starter project templates: x402-starter-kit | create-x402

Create a .env file or set environment variables directly. Example .env:

HOST=0.0.0.0
PORT=8080
RPC_URL_BASE_SEPOLIA=https://sepolia.base.org
RPC_URL_BASE=https://mainnet.base.org
SIGNER_TYPE=private-key
EVM_PRIVATE_KEY=0xdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef
SOLANA_PRIVATE_KEY=6ASf5EcmmEHTgDJ4X4ZT5vT6iHVJBXPg5AN5YoTCpGWt
RUST_LOG=info

Important: The supported networks are determined by which RPC URLs you provide:

• If you set only RPC_URL_BASE_SEPOLIA, then only Base Sepolia network is supported.
• If you set both RPC_URL_BASE_SEPOLIA and RPC_URL_BASE, then both Base Sepolia and Base Mainnet are supported.
• If an RPC URL for a network is missing, that network will not be available for settlement or verification.

Build a Docker image locally:

docker build -t x402-facilitator .
docker run --env-file .env -p 8080:8080 x402-facilitator

The container:

• Exposes port 8080 (or a port you configure with PORT environment variable).
• Starts on http://localhost:8080 by default.
• Requires minimal runtime dependencies (based on debian:bullseye-slim).

If you are building an x402-powered application, update the Facilitator URL to point to your self-hosted instance. An example is the x402 payment link project.

ℹ️ Tip: For production deployments, ensure your Facilitator is reachable via HTTPS and protect it against public abuse.

The service reads configuration via .env file or directly through environment variables.

Available variables:

• RUST_LOG: Logging level (e.g., info, debug, trace),
• HOST: HTTP host to bind to (default: 0.0.0.0),
• PORT: HTTP server port (default: 8080),
• SIGNER_TYPE (required): Type of signer to use. Only private-key is supported now,
• EVM_PRIVATE_KEY (required): Private key in hex for EVM networks, like 0xdeadbeef...,
• SOLANA_PRIVATE_KEY (required): Private key in hex for Solana networks, like 0xdeadbeef...,
• RPC_URL_BASE_SEPOLIA: Ethereum RPC endpoint for Base Sepolia testnet,
• RPC_URL_BASE: Ethereum RPC endpoint for Base mainnet,
• RPC_URL_AVALANCHE_FUJI: Ethereum RPC endpoint for Avalanche Fuji testnet,
• RPC_URL_AVALANCHE: Ethereum RPC endpoint for Avalanche C-Chain mainnet.
• RPC_URL_SOLANA: RPC endpoint for Solana mainnet.
• RPC_URL_SOLANA_DEVNET: RPC endpoint for Solana devnet.
• RPC_URL_POLYGON: RPC endpoint for Polygon mainnet.
• RPC_URL_POLYGON_AMOY: RPC endpoint for Polygon Amoy testnet.
• RPC_URL_SEI: RPC endpoint for Sei mainnet.
• RPC_URL_SEI_TESTNET: RPC endpoint for Sei testnet.

The facilitator emits OpenTelemetry-compatible traces and metrics to standard endpoints, making it easy to integrate with tools like Honeycomb, Prometheus, Grafana, and others. Tracing spans are annotated with HTTP method, status code, URI, latency, other request and process metadata.

To enable tracing and metrics export, set the appropriate OTEL_ environment variables:

# For Honeycomb, for example:
# Endpoint URL for sending OpenTelemetry traces and metrics
OTEL_EXPORTER_OTLP_ENDPOINT=https://api.honeycomb.io:443
# Comma-separated list of key=value pairs to add as headers
OTEL_EXPORTER_OTLP_HEADERS=x-honeycomb-team=your_api_key,x-honeycomb-dataset=x402-rs
# Export protocol to use for telemetry. Supported values: `http/protobuf` (default), `grpc`
OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf

The service automatically detects and initializes exporters if OTEL_EXPORTER_OTLP_* variables are provided.

Prerequisites:

• Rust 1.80+
• cargo and a working toolchain

Build locally:

cargo build

Run:

cargo run

• x402 Protocol Documentation
• x402 Overview by Coinbase
• Facilitator Documentation by Coinbase

Apache-2.0