Onchain is x402's Intelligent Intermediary Layer
Securely move money at the speed of light online
Powered by the integration of leading x402 facilitators
Send USDC payments through the intelligent intermediary layer
💡 How it works: Your payment is signed, verified, and settled through the optimal x402 facilitator. Gasless USDC transfers with maximum efficiency on Base and Solana.
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Why Onchain?
Onchain is a payment aggregator for x402 payments. Supporting Base, Solana, and cross-chain payments, Onchain routes your payments across multiple facilitators with intelligent selection and automatic failover. Additional networks launching progressively.
🔄 Multi-Facilitator Routing + Cross-Chain
Access multiple x402 facilitators (Coinbase CDP, x402.rs, Daydreams, Aurracloud, OpenX402, thirdweb, PayAI, OctonetAI, Anyspend, Heurist, Treasure, Corbits) through a single integration. Supports same-chain (Base → Base, Solana → Solana) and cross-chain payments (Solana → Base, Base → Solana). Automatic failover if one facilitator is down.
🎯 Intelligent Selection
Optimize for speed, cost, or reliability. Onchain scores each facilitator in real-time and routes to the optimal one based on your priority.
🌐 Language Agnostic
Simple REST API works with any programming language. Python, Node.js, Go, Ruby, PHP, Java, Rust - just make HTTP requests. No SDK dependencies required.
⚡ Production Ready
Battle-tested error handling, automatic retries, health monitoring, and rate limiting. Built for production from day one.
⚡ Uplink SDK - Simplest Integration
Our JavaScript/TypeScript SDK abstracts away the complexity. Just install, configure, and make payments in 12 lines of code.
# Install
npm install @onchainfi/uplink
# Usage
import { Uplink } from '@onchainfi/uplink';
const uplink = new Uplink({
apiKey: process.env.ONCHAIN_API_KEY,
privateKey: process.env.UPLINK_PRIVATE_KEY,
network: 'base',
createAtaFeeAcceptance: true,
minimumCrosschainFeeAcceptance: true,
});
const txHash = await uplink.pay({
to: '0xRecipient...',
amount: '$10'
});
console.log(`Payment sent! TX: ${txHash}`);Works on Base and Solana • Supports same-chain and cross-chain payments • Built-in retry logic and error handling
REST API Integration
Call our API from any programming language. Works with Python, Node.js, Go, Ruby, PHP, Java, Rust, or any HTTP client.
🚨 Important: Sign to Intermediate Address
The x402 payment must be signed to the correct intermediate address (NOT directly to the final recipient):
0xfeb1F8F7F9ff37B94D14c88DE9282DA56b3B1Cb1DoVABZK8r9793SuR3powWCTdr2wVqwhueV9DuZu97n2L0x931Cc2F11C36C34b4312496f470Ff21474F2fA42AGm6Dzvd5evgWGGZtyvJE7cCTg7DKC9dNmwdubJg2toqThe to parameter is your final recipient. The backend validates your signature is to the correct intermediate.
# Step 1: Sign x402 payment to intermediate address
# (Use your wallet SDK to create x402 signature)
# Step 2: Call /pay with final recipient
curl -X POST https://api.onchain.fi/v1/pay \
-H "X-API-Key: your-api-key" \
-H "Content-Type: application/json" \
-d '{
"paymentHeader": "base64-signed-to-intermediate",
"to": "0xFinalRecipient...",
"sourceNetwork": "base",
"destinationNetwork": "base",
"expectedAmount": "1.00",
"expectedToken": "USDC",
"priority": "balanced"
}'
# Response
{
"status": "success",
"data": {
"txHash": "0x...",
"verified": true,
"settled": true,
"facilitator": "Coinbase CDP"
}
}See API Documentation for detailed examples and other endpoints.