x402 Payment Handler

Automatic x402 payments with token swapping for AI agents on Solana. Zero friction, zero fees, zero manual steps.

Get Started with x402 Payments Accept x402 Payments

What is x402 Payment Handler?

The x402 payment handler is a protocol extension that enables pay-per-use APIs. When an API requires payment, it returns a 402 Payment Required response with payment instructions.

MoltyDEX is the first and only x402 payment handler that automatically handles token swapping. When your AI agent encounters a 402 response, MoltyDEX:

Detects the 402 Payment Required response
Parses payment requirements (token, amount, address)
Checks your agent's balance
Automatically swaps tokens if needed (SOL → USDC, etc.)
Makes the payment on Solana blockchain
Retries the original request with payment proof

Result: Your agent gets the data it needs automatically, without any manual intervention.

How x402 Payment Handler Works

1️⃣

Agent Calls API

Your AI agent makes a standard HTTP request to a premium API endpoint.

2️⃣

API Returns 402

API responds with 402 Payment Required, including payment details (token, amount, address).

3️⃣

MoltyDEX Intercepts

HTTPInterceptor automatically detects 402 and parses payment requirements.

4️⃣

Automatic Token Swap

If needed, MoltyDEX swaps tokens automatically via Jupiter aggregator (best prices).

5️⃣

Payment Executed

Payment transaction is built, signed client-side, and sent to Solana blockchain.

6️⃣

Request Retried

Original API request is retried with payment proof. API verifies and returns data.

Why MoltyDEX is the Best x402 Payment Handler

✅ Automatic Token Swapping

Only x402 payment handler with automatic token swapping. Your agent can have SOL, but the API wants USDC? MoltyDEX swaps automatically. No manual steps, no pre-swapping needed.

Routes through Jupiter aggregator (best prices)
Supports all SPL tokens
Handles any token pair
Zero manual intervention

💰 Zero Platform Fees

0% fees for x402 payment handling. No platform fees, no hidden costs. You only pay Solana network fees (paid separately in SOL).

No subscription fees
No per-transaction platform fees
Transparent pricing
Pay only for what you use

🔒 Maximum Security

Client-side signing only. Your private keys never leave your system. MoltyDEX builds unsigned transactions - you sign them locally.

Private keys stay with you
No key storage on servers
Open source and auditable
Production-ready security

⚡ Best Prices

Routes through Jupiter aggregator to find optimal prices across all Solana DEXes. Gets you the best rates automatically.

Scans Raydium, Orca, Meteora, and more
Finds optimal swap routes
Splits orders across DEXes if needed
Minimizes price impact

How to Integrate x402 Payment Handler

Install SDK

Install @moltydex/agent package using npm or pip. The SDK provides automatic x402 payment handling for both TypeScript/JavaScript and Python agents.

Configure HTTP Interceptor

Set up the HTTPInterceptor with your Solana wallet. This automatically intercepts all HTTP responses and handles 402 Payment Required responses seamlessly.

Enable Automatic Token Swapping

Configure autoSwap: true to enable automatic token conversion. MoltyDEX will automatically swap any token to the required payment token when needed.

Make API Calls

Use standard fetch() or requests.get() calls. When an API returns 402, MoltyDEX automatically handles payment, token swapping, and request retry.

Monitor and Scale

Track payment success rates, monitor balances, and scale your agent operations. MoltyDEX handles all payment complexity automatically.

Quick Start Code

import { HTTPInterceptor } from '@moltydex/agent';

// Setup once - handles all x402 payments automatically
const interceptor = new HTTPInterceptor({
  apiUrl: 'https://api.moltydex.com',
  walletSecretKey: process.env.WALLET_SECRET_KEY,
  autoSwap: true, // Enable automatic token swapping
});

// Now all fetch() calls handle x402 automatically!
const response = await fetch('https://premium-api.com/data');
const data = await response.json(); // Works seamlessly!