x402 supports multiple blockchain networks for payment processing. This page covers what the x402 reference SDKs support, what the CDP facilitator is configured for, and where to find other facilitators.
Network Identifiers (CAIP-2)
x402 v2 uses CAIP-2 (Chain Agnostic Improvement Proposal) format for network identifiers. This provides a standardized way to identify blockchain networks across the ecosystem.
The format is: namespace:reference
- EVM Networks:
eip155:{chainId} where chainId is the EVM chain ID
- Solana Networks:
solana:{genesisHash} where genesisHash is a truncated genesis hash
Examples
// EVM networks
network: "eip155:8453" // Base mainnet (chain ID 8453)
network: "eip155:84532" // Base Sepolia (chain ID 84532)
network: "eip155:1" // Ethereum mainnet (chain ID 1)
// Solana networks
network: "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp" // Solana mainnet
network: "solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1" // Solana devnet
Reference SDK Support
The x402 reference SDKs are designed to be flexible and extensible:
EVM Support (@x402/evm)
The @x402/evm package supports any EVM-compatible chain you configure, as long as the payment asset implements EIP-3009 (Transfer With Authorization). This includes:
- Any Ethereum L1 or L2
- Any EVM-compatible chain with a valid chain ID
- Any EIP-3009 compliant token (USDC, EURC, etc.)
Solana Support (@x402/svm)
The @x402/svm package supports any Solana cluster with:
- SPL Token Program tokens
- Token2022 program tokens
Other SDKs
Community and third-party SDKs may expand support to other protocol families or chains beyond what the reference SDKs currently support. Check the x402 ecosystem for additional implementations.
CDP Facilitator Support
The CDP (Coinbase Developer Platform) facilitator is configured to support the following networks and schemes:
| Network | CAIP-2 Identifier | v1 Support | v2 Support | Scheme | Fees |
|---|
| Base | eip155:8453 | ✅ | ✅ | exact | Fee-free* |
| Base Sepolia | eip155:84532 | ✅ | ✅ | exact | Fee-free* |
| Solana | solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp | ✅ | ✅ | exact | Fee-free* |
| Solana Devnet | solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1 | ✅ | ✅ | exact | Fee-free* |
- Mainnet:
https://api.cdp.coinbase.com/platform/v2/x402
- Requires CDP API keys
- Supports: Base, Solana
x402.org Testnet Facilitator
The x402.org testnet facilitator is available for testing and development:
| Network | CAIP-2 Identifier | v1 Support | v2 Support | Scheme |
|---|
| Base Sepolia | eip155:84532 | ✅ | ✅ | exact |
| Solana Devnet | solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1 | ✅ | ✅ | exact |
https://x402.org/facilitator
- No API key required
- For testnet use only
Other Facilitators
The x402 protocol is permissionless, so anyone can run a facilitator. The ecosystem includes several community and third-party facilitators that support additional networks, tokens, and features.
For a complete and up-to-date list of facilitators, visit the x402 Ecosystem. Chain ID Reference
Quick reference for common EVM chain IDs:
| Chain ID | Network | CAIP-2 Format |
|---|
| 1 | Ethereum Mainnet | eip155:1 |
| 10 | Optimism | eip155:10 |
| 137 | Polygon | eip155:137 |
| 8453 | Base | eip155:8453 |
| 84532 | Base Sepolia | eip155:84532 |
| 42161 | Arbitrum One | eip155:42161 |
| 43114 | Avalanche C-Chain | eip155:43114 |
| 43113 | Avalanche Fuji | eip155:43113 |
Token Support
EVM Networks (EIP-3009)
On EVM networks, x402 supports tokens that implement EIP-3009 (Transfer With Authorization). This enables gasless transfers where the user signs a message and the facilitator submits the transaction.
Common EIP-3009 Tokens:
| Token | Base | Base Sepolia |
|---|
| USDC | 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 | 0x036CbD53842c5426634e7929541eC2318f3dCF7e |
Any EIP-3009 compliant token can be used with x402. The token addresses above are the most commonly used with the CDP facilitator.
Solana Networks (SPL / Token2022)
On Solana, x402 supports both SPL Token Program and Token2022 program tokens.
Common Tokens:
| Token | Mainnet | Devnet |
|---|
| USDC | EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v | (faucet available) |
// Dollar string format (recommended for readability)
price: "$0.001" // 0.001 USDC
price: "$1.00" // 1 USDC
price: "$0.50" // 0.50 USDC
// Atomic units (for precision)
amount: "1000" // 0.001 USDC (6 decimals)
amount: "1000000" // 1 USDC (6 decimals)
Usage Examples
Server-Side Configuration
import { paymentMiddleware, x402ResourceServer } from "@x402/express";
import { ExactEvmScheme } from "@x402/evm/exact/server";
import { HTTPFacilitatorClient } from "@x402/core/server";
const facilitatorClient = new HTTPFacilitatorClient({
url: "https://x402.org/facilitator",
});
// Register scheme for Base Sepolia
const server = new x402ResourceServer(facilitatorClient)
.register("eip155:84532", new ExactEvmScheme());
app.use(
paymentMiddleware(
{
"GET /api": {
accepts: [
{
scheme: "exact",
price: "$0.001",
network: "eip155:84532", // Base Sepolia
payTo: "0xYourAddress",
},
],
description: "API endpoint",
},
},
server,
),
);
import (
x402 "github.com/coinbase/x402/go"
x402http "github.com/coinbase/x402/go/http"
evm "github.com/coinbase/x402/go/mechanisms/evm/exact/server"
)
network := x402.Network("eip155:84532") // Base Sepolia
r.Use(ginmw.X402Payment(ginmw.Config{
Routes: x402http.RoutesConfig{
"GET /api": {
Scheme: "exact",
PayTo: payTo,
Price: "$0.001",
Network: network,
},
},
Facilitator: facilitatorClient,
Schemes: []ginmw.SchemeConfig{
{Network: network, Server: evm.NewExactEvmScheme()},
},
}))
Using a Custom Network
Since @x402/evm supports any EVM chain, you can configure networks not listed above:
// Example: Using Ethereum mainnet with a custom facilitator
const facilitatorClient = new HTTPFacilitatorClient({
url: "https://example.facilitator.com",
});
const server = new x402ResourceServer(facilitatorClient)
.register("eip155:1", new ExactEvmScheme()); // Ethereum mainnet
app.use(
paymentMiddleware(
{
"GET /api": {
accepts: [
{
scheme: "exact",
price: "$0.001",
network: "eip155:1",
payTo: "0xYourAddress",
asset: "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48", // USDC on Ethereum
},
],
description: "API endpoint",
},
},
server,
),
);
Multi-Network Support
Support multiple networks on the same endpoint:
{
"GET /api": {
accepts: [
{
scheme: "exact",
price: "$0.001",
network: "eip155:8453", // Base mainnet
payTo: "0xYourEvmAddress",
},
{
scheme: "exact",
price: "$0.001",
network: "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp", // Solana mainnet
payTo: "YourSolanaAddress",
},
],
description: "Multi-network endpoint",
},
}
Running Your Own Facilitator
If you need to support networks or tokens not available through existing facilitators, you can run your own:
- Use the reference implementation: The x402 GitHub repository contains facilitator code
- Use a community implementation: Check the x402 Ecosystem for self-hostable options
Next Steps
