Networks & Token Support

Documentation Index

Fetch the complete documentation index at: https://docs.x402.org/llms.txt

Use this file to discover all available pages before exploring further.

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Network Identifiers (CAIP-2)

• EVM networks: eip155:<chainId> — any EVM chain is supported (e.g., eip155:8453 for Base)
• Solana: solana:<genesisHash> (first 32 bytes of the genesis block hash)
• Algorand: algorand:<genesisHash> (base64-encoded genesis hash)
• Stellar: stellar:<network> (pubnet or testnet)
• Aptos: aptos:<chainId> (e.g., aptos:1 for mainnet)

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Token Support

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EVM: Asset Transfer Methods

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Specifying Payment Amounts

1. Price String (e.g., "$0.01") — The system uses the chain’s default stablecoin. Only works on chains with a configured default.
2. TokenAmount — Specify exact amountInAtomicUnits + asset address. Works on any chain with no configuration needed.

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Using Custom ERC-20 Tokens

1. Token Address: The contract address of your ERC-20 token
2. EIP-712 Name: The token’s name for EIP-712 signatures
3. EIP-712 Version: The token’s version for EIP-712 signatures

1. Name: Read the name() function - Example on Basescan
2. Version: Read the version() function - Example on Basescan

{
  eip712: {
    name: "USD Coin",    // From name() function
    version: "2"         // From version() function
  }
}

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Default Assets for Dollar-String Pricing

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EVM

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Solana (SVM)

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Algorand (AVM)

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Stellar

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Aptos

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Adding Support for New Networks

1. Runtime Registration — use any network in your own server code without modifying the x402 source. No PR required.
2. Contributing a New Default Asset — upstream a chain so it appears in the default-asset tables above and supports "$0.01" dollar-string pricing out of the box. Requires a PR updating the TypeScript, Go, and Python SDK registries.

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Runtime Registration

import { x402ResourceServer, HTTPFacilitatorClient } from "@x402/core/server";
import { ExactEvmScheme } from "@x402/evm/exact/server";

const facilitatorClient = new HTTPFacilitatorClient({
  url: "https://your-facilitator.com"  // Facilitator that supports your network
});

const server = new x402ResourceServer(facilitatorClient);
server.register("eip155:*", new ExactEvmScheme());

const routes = {
  "GET /api/data": {
    accepts: [{
      scheme: "exact",
      price: "$0.001",
      network: "eip155:43114",  // Avalanche mainnet
      payTo: "0xYourAddress",
    }],
  },
};

import (
    x402http "github.com/x402-foundation/x402/go/http"
    evm "github.com/x402-foundation/x402/go/mechanisms/evm/exact/server"
)

facilitatorClient := x402http.NewHTTPFacilitatorClient(&x402http.FacilitatorConfig{
    URL: "https://your-facilitator.com",
})

schemes := []ginmw.SchemeConfig{
    {Network: x402.Network("eip155:43114"), Server: evm.NewExactEvmScheme()},  // Avalanche
}

from x402.http import FacilitatorConfig, HTTPFacilitatorClient, PaymentOption
from x402.http.types import RouteConfig
from x402.mechanisms.evm.exact import ExactEvmServerScheme
from x402.server import x402ResourceServer

facilitator = HTTPFacilitatorClient(
    FacilitatorConfig(url="https://your-facilitator.com")
)

server = x402ResourceServer(facilitator)
server.register("eip155:43114", ExactEvmServerScheme())  # Avalanche mainnet
routes: dict[str, RouteConfig] = {
    "GET /api/data": RouteConfig(
        accepts=[
            PaymentOption(
                scheme="exact",
                price="$0.001",
                network="eip155:43114",
                pay_to="0xYourAddress",
            ),
        ],
    ),
}

• Use CAIP-2 format: eip155:<chainId> for any EVM network
• The scheme implementation handles the network automatically
• You only need a facilitator that supports your target network (or run your own)

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Contributing a New Default Asset

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Facilitators

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x402.org Facilitator

• Supports: eip155:84532 (Base Sepolia), solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1 (Solana Devnet), stellar:testnet (Stellar Testnet), aptos:2 (Aptos Testnet)
• Notes: Recommended for testing and development. This is the default facilitator in the x402 packages and requires no setup.

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Production Facilitators

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Quick Reference

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Running Your Own Facilitator

1. Access to an RPC endpoint for your target network
2. A wallet with native tokens for gas sponsorship
3. The x402 facilitator code

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Getting Help

• Join the x402 Discord community
• Check the x402 GitHub repository

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Summary

• Any EVM chain is supported via eip155:<chainId> — plus Solana, Stellar, and Aptos
• Default assets are a convenience for "$0.01" dollar-string pricing; explicit TokenAmount works on any chain
• Any ERC-20 token works on any EVM facilitator (via EIP-3009 or Permit2)
• CAIP-2 identifiers provide unambiguous cross-chain support

• Quickstart for Sellers — Start accepting payments on supported networks
• Core Concepts — Learn how x402 works under the hood
• Facilitator — Understand the role of facilitators
• MCP Server — Set up AI agents to use x402 payments