> ## 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. # Networks & Token Support > This page explains which blockchain networks and tokens are supported by x402, and how to extend support to additional networks. ## Network Identifiers (CAIP-2) x402 uses [CAIP-2](https://chainagnostic.org/CAIPs/caip-2) standard network identifiers (`namespace:reference`) for unambiguous cross-chain support: * **EVM networks**: `eip155:` — any EVM chain is supported (e.g., `eip155:8453` for Base) * **Solana**: `solana:` (first 32 bytes of the genesis block hash) * **Algorand**: `algorand:` (base64-encoded genesis hash) * **Stellar**: `stellar:` (`pubnet` or `testnet`) * **Aptos**: `aptos:` (e.g., `aptos:1` for mainnet) * **Hedera**: `hedera:` (`mainnet` or `testnet`) ## Token Support x402 supports tokens on EVM, Solana, Stellar, Aptos, and Hedera networks: | Ecosystem | Supported Tokens | Transfer Method | | ----------- | ------------------------------------- | ---------------------------------- | | **EVM** | Any ERC-20 token | EIP-3009 or Permit2 | | **Solana** | Any SPL or Token-2022 token | SPL Transfer | | **Stellar** | Any Soroban token implementing SEP-41 | `transfer(from, to, amount)` | | **Aptos** | Any fungible asset | `primary_fungible_store::transfer` | | **Hedera** | HBAR or any HTS fungible token | Hedera Transfer Transaction | Facilitators support **networks**, not specific tokens — any compatible token works on any facilitator that supports that network. ### EVM: Asset Transfer Methods x402 supports two asset transfer methods on EVM, selected automatically based on token capabilities: | Method | When Used | How It Works | | ------------ | ---------------------------------------------------- | -------------------------------------------------------------------------------------------------------------- | | **EIP-3009** | Tokens with `transferWithAuthorization` (e.g., USDC) | Single off-chain signature, simplest flow | | **Permit2** | Any ERC-20 token | Uses Uniswap's [Permit2](https://docs.uniswap.org/contracts/v4/deployments) contract + `x402ExactPermit2Proxy` | Both methods provide gasless transfers (facilitator sponsors gas), signature-based authorization, and secure payments. EIP-3009 is preferred when available (simpler, no approval step). Permit2 serves as the universal fallback. **Permit2 approval**: Requires a one-time on-chain approval. x402 supports two gas sponsoring extensions that make this step gasless — see [EIP-2612 Gas Sponsoring](/extensions/eip2612-gas-sponsoring) and [ERC-20 Approval Gas Sponsoring](/extensions/erc20-approval-gas-sponsoring). ### Specifying Payment Amounts When configuring payment requirements, you have two options: 1. **Price String** (e.g., `"$0.01"`) — The system uses the chain's [default stablecoin](#default-assets-for-dollar-string-pricing). Only works on chains with a configured default. 2. **TokenAmount** — Specify exact `amountInAtomicUnits` + asset address. Works on **any chain** with no configuration needed. ### Using Custom ERC-20 Tokens To use a custom ERC-20 token, you need three key pieces of information: 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 You can retrieve these from any block explorer: 1. **Name**: Read the `name()` function - [Example on Basescan](https://basescan.org/token/0x833589fcd6edb6e08f4c7c32d4f71b54bda02913#readProxyContract#F16) 2. **Version**: Read the `version()` function - [Example on Basescan](https://basescan.org/token/0x833589fcd6edb6e08f4c7c32d4f71b54bda02913#readProxyContract#F24) These values are used in the `eip712` nested object when configuring TokenAmount: ```typescript theme={null} { eip712: { name: "USD Coin", // From name() function version: "2" // From version() function } } ``` ## Default Assets for Dollar-String Pricing When you use `"$0.01"` syntax, x402 needs to know which stablecoin to use. The following chains have pre-configured defaults. For chains not listed, use `registerMoneyParser()` or specify the price directly as a `TokenAmount` with `amountInAtomicUnits`. To contribute a new default asset, see [Contributing a New Default Asset](#contributing-a-new-default-asset) below. ### EVM | Chain | CAIP-2 | Token Address | EIP-712 Name | Decimals | Transfer Method | | ---------------- | --------------- | -------------------------------------------- | ------------ | -------- | ------------------ | | Base | `eip155:8453` | `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913` | USD Coin | 6 | EIP-3009 | | Base Sepolia | `eip155:84532` | `0x036CbD53842c5426634e7929541eC2318f3dCF7e` | USDC | 6 | EIP-3009 | | Polygon | `eip155:137` | `0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359` | USD Coin | 6 | EIP-3009 | | Arbitrum One | `eip155:42161` | `0xaf88d065e77c8cC2239327C5EDb3A432268e5831` | USD Coin | 6 | EIP-3009 | | Arbitrum Sepolia | `eip155:421614` | `0x75faf114eafb1BDbe2F0316DF893fd58CE46AA4d` | USD Coin | 6 | EIP-3009 | | Monad | `eip155:143` | `0x754704Bc059F8C67012fEd69BC8A327a5aafb603` | USD Coin | 6 | EIP-3009 | | Stable | `eip155:988` | `0x779Ded0c9e1022225f8E0630b35a9b54bE713736` | USDT0 | 6 | EIP-3009 | | Stable Testnet | `eip155:2201` | `0x78Cf24370174180738C5B8E352B6D14c83a6c9A9` | USDT0 | 6 | EIP-3009 | | MegaETH | `eip155:4326` | `0xFAfDdbb3FC7688494971a79cc65DCa3EF82079E7` | MegaUSD | 18 | Permit2 + EIP-2612 | | Mezo Testnet | `eip155:31611` | `0x118917a40FAf1CD7a13dB0Ef56C86De7973Ac503` | Mezo USD | 18 | Permit2 + EIP-2612 | | Radius | `eip155:723487` | `0x33ad9e4BD16B69B5BFdED37D8B5D9fF9aba014Fb` | Stable Coin | 6 | Permit2 + EIP-2612 | | Radius Testnet | `eip155:72344` | `0x33ad9e4BD16B69B5BFdED37D8B5D9fF9aba014Fb` | Stable Coin | 6 | Permit2 + EIP-2612 | ### Solana (SVM) | Chain | CAIP-2 | Token Mint | Decimals | | -------------- | ----------------------------------------- | ----------------------------------------------------- | -------- | | Solana Mainnet | `solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp` | `EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v` (USDC) | 6 | | Solana Devnet | `solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1` | `4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU` (USDC) | 6 | ### Algorand (AVM) | Chain | CAIP-2 | ASA ID | Decimals | | ---------------- | ------------------------------------------------------- | ----------------- | -------- | | Algorand Mainnet | `algorand:wGHE2Pwdvd7S12BL5FaOP20EGYesN73ktiC1qzkkit8=` | `31566704` (USDC) | 6 | | Algorand Testnet | `algorand:SGO1GKSzyE7IEPItTxCByw9x8FmnrCDexi9/cOUJOiI=` | `10458941` (USDC) | 6 | ### Stellar | Chain | CAIP-2 | Token Contract | Decimals | | --------------- | ----------------- | ----------------------------------------------------------------- | -------- | | Stellar Pubnet | `stellar:pubnet` | `CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75` (USDC) | 7 | | Stellar Testnet | `stellar:testnet` | `CBIELTK6YBZJU5UP2WWQEUCYKLPU6AUNZ2BQ4WWFEIE3USCIHMXQDAMA` (USDC) | 7 | ### Aptos | Chain | CAIP-2 | Fungible Asset Address | Decimals | | ------------- | --------- | --------------------------------------------------------------------------- | -------- | | Aptos Mainnet | `aptos:1` | `0xbae207659db88bea0cbead6da0ed00aac12edcdda169e591cd41c94180b46f3b` (USDC) | 6 | | Aptos Testnet | `aptos:2` | `0x69091fbab5f7d635ee7ac5098cf0c1efbe31d68fec0f2cd565e8d168daf52832` (USDC) | 6 | ### Hedera | Chain | CAIP-2 | Token ID | Decimals | | -------------- | ---------------- | ------------------- | -------- | | Hedera Mainnet | `hedera:mainnet` | `0.0.456858` (USDC) | 6 | | Hedera Testnet | `hedera:testnet` | `0.0.429274` (USDC) | 6 | HBAR (native token) is also supported using asset ID `0.0.0`, with amounts in tinybars (1 HBAR = 10⁸ tinybars). ## Adding Support for New Networks There are two distinct paths, depending on your goal: 1. **[Runtime Registration](#runtime-registration)** — use any network in your own server code without modifying the x402 source. No PR required. 2. **[Contributing a New Default Asset](#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. ### Runtime Registration x402 uses dynamic network registration — you can support any EVM network without modifying source files. ```typescript theme={null} 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", }], }, }; ``` ```go theme={null} 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 } ``` ```python theme={null} 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", ), ], ), } ``` **Key Points:** * Use CAIP-2 format: `eip155:` 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) ### Contributing a New Default Asset To add a chain to the [default-asset tables above](#default-assets-for-dollar-string-pricing) so that dollar-string pricing (`"$0.01"`) works out of the box, open a PR against [x402-foundation/x402](https://github.com/x402-foundation/x402). Follow the cross-SDK walkthrough in [DEFAULT\_ASSETS.md](https://github.com/x402-foundation/x402/blob/main/DEFAULT_ASSETS.md), which names every file in the TypeScript, Go, and Python registries that must be updated. ## Facilitators Network support in x402 depends on which facilitator you use. For a complete list, see the [x402 Ecosystem](https://www.x402.org/ecosystem?filter=facilitators). ### 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. ### Production Facilitators Multiple production-ready facilitators are available supporting various networks including Base, Solana, Polygon, Avalanche, and more. See the [x402 Ecosystem](https://www.x402.org/ecosystem?filter=facilitators) for available options. ### Quick Reference | Facilitator Type | Networks Supported | Production Ready | Requirements | | ----------------------------------------------------------------------------- | --------------------------------------------------------------------------------------- | ---------------- | --------------- | | x402.org (Default) | `eip155:84532`, `solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1`, `stellar:testnet`, `aptos:2` | Testnet only | None | | [Production Facilitators](https://www.x402.org/ecosystem?filter=facilitators) | Various (Base, Solana, Polygon, Avalanche, etc.) | Yes | Varies | | Self-hosted | Any network | Yes | Technical setup | ### Running Your Own Facilitator If you need immediate support or want to test before contributing, you can run your own facilitator. Video Guide: [Adding EVM Chains to x402](https://x.com/jaycoolh/status/1920851551905575164/video/1) **Prerequisites** 1. Access to an RPC endpoint for your target network 2. A wallet with native tokens for gas sponsorship 3. The x402 facilitator code ## Getting Help * Join the [x402 Discord community](https://discord.gg/cdp) * Check the [x402 GitHub repository](https://github.com/x402-foundation/x402) ## Summary Key takeaways: * **Any EVM chain** is supported via `eip155:` — plus Solana, Stellar, Aptos, and Hedera * [Default assets](#default-assets-for-dollar-string-pricing) 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 Next, explore: * [Quickstart for Sellers](/getting-started/quickstart-for-sellers) — Start accepting payments on supported networks * [Core Concepts](/core-concepts/http-402) — Learn how x402 works under the hood * [Facilitator](/core-concepts/facilitator) — Understand the role of facilitators * [MCP Server](/guides/mcp-server-with-x402) — Set up AI agents to use x402 payments