x402 payments

x402 lets you charge for an API call over plain HTTP. Your API answers an unpaid request with 402 Payment Required and a price. The buyer, often an AI agent, signs a stablecoin payment and retries. Cryptonly settles it on-chain, and your API returns the response.

Read the quickstart Open dashboard

How it works

Cryptonly is the facilitator: it checks the signed payment, sends it to the network and pays the network fee.

No gas for buyers

Buyers hold only stablecoins. Cryptonly pays the ETH or SOL for the transfer.

Paid to your wallet

Payments go straight to your own wallet, or on Base to your Cryptonly balance.

Prices without deploys

Set prices in the dashboard and change them at any time. Or keep them in code.

Every payment tracked

Payment history, CSV export and webhooks for each call.

Networks and assets

• BaseUSDCEURCeip155:8453
• SolanaUSDCUSDTsolana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp

Choose which assets you accept under Settings → General → Accepted assets. An endpoint priced in the dashboard can have a price in each of them; its 402 offers them all. The sandbox uses Base Sepolia (eip155:84532) and Solana Devnet (solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1).

Pricing

The first 100 payments each month are free. After that, each payment costs $0.0025. See how fees are paid.

Get started

Prices in the dashboardRecommended. Quickstart for Express, Fastify or NestJS, from wallet to first payment.

Prices in your codeNestJS, or stock x402 middleware for Express, Fastify, Hono, Next.js, FastAPI, Flask or Go.

Related pages

Invoices for AI agentsLet agents pay your invoices with x402

x402 API referencesupported, config, verify, settle and settlements