x402 Protocol

x402 is an open internet-native payment standard built on HTTP 402 "Payment Required". It enables instant stablecoin payments over ordinary HTTP flows, designed for AI agent autonomy.

How x402 Works

When an agent requests a protected resource, the server responds with HTTP 402 and a Payment-Required header. The agent reads the requirements, creates a signed payment authorization, and retries the request with a Payment-Signature header.

Key Concepts

• Scheme — The payment method. Zeny supports "exact" (one-time USDM transfer).
• Network — The blockchain. Zeny uses MegaETH (chain ID 4326).
• Asset — The settlement token. Zeny uses USDM.
• Facilitator — The service that verifies and settles. That's Zeny.

Why x402?

• No accounts, no sessions, no API keys
• AI agents can autonomously parse and pay
• Cryptographic signatures prevent unauthorized fund movement
• Backed by Coinbase, Cloudflare, Linux Foundation

See the detailed payment flow for step-by-step walkthrough.