What Is x402? How AI Agents Pay With Crypto

What it claims

x402 is a protocol, not a chain or coin. It defines message formats, headers and a request/response flow on top of HTTP. Payments are mostly USDC on Base. The article says it also supports Solana, Polygon, Arbitrum and others, plus traditional card payments. x402 has no official token. Speculative "x402" tokens on various chains are not issued or backed by Coinbase or the x402 Foundation.

How it works

1. A client requests a resource, such as an API call, a dataset or an article.
2. The server returns 402 with machine-readable terms: the price, the accepted tokens and the payee wallet address.
3. The client signs a payment authorization and resends the request with the signature in a header.
4. The server verifies the payment, settles it onchain (usually through a facilitator) and returns the resource.

On EVM chains, the signature is an EIP-3009 transfer authorization, so the buyer does not need ETH for gas. The facilitator means sellers do not run their own crypto infrastructure.

V2 (December 2025) added three things: wallet-based identity, so agents need not pay again on every call; automatic service discovery; and more chains. Batch settlement (May 2026) lets agents give sellers signed vouchers that are settled in bulk.

Evidence

Fireblocks, citing agenteconomy.to, reports more than 196 million transactions across 12 chains and over $42 million settled as of November 1, 2026. Coinbase says x402 carried more than 97% of onchain agent transactions in Q2 2026.

Fireblocks also reports that more than half of lifetime transactions came from a two-month burst in late 2025. In that period, scripts minted and traded PING, a token issued through x402. October 2026 volume was 5.1 million transactions worth about $274,000, roughly 5 cents per transaction. Cloudflare reports seeing a billion HTTP 402 responses a day on its network.

How to use it

A buyer needs a wallet holding a supported stablecoin on a supported network, usually USDC on Base. Coinbase Developer Platform wallets and Circle Wallets can fund agents and set spending limits. Integrations named in the article:

• Cloudflare: x402 support in its Agents SDK, plus an edge monetization gateway.
• Stripe: converts x402 payments into standard PaymentIntents, with fiat reporting and payouts.
• AWS AgentCore: manages buyer-side payments, budgets and permissions.
• Google: an A2A x402 extension within AP2.
• Agentic.Market: Coinbase's directory of x402 services with live pricing, launched April 2026.
• CoinGecko: sells pay-per-call market data endpoints.

Limits

This is a news explainer. It has no spec details, header names, SDK commands or code. Governance moved to the Linux Foundation's x402 Foundation, which became operational on July 14, 2026. It now has 57 members, and Michael Hursta has been executive director since October 1, 2026.

Several x402 Foundation members back competing standards:

• Agentic Commerce Protocol: from Stripe and OpenAI.
• Trusted Agent Protocol: from Visa.
• Machine Payments Protocol: from Stripe and Tempo. It also uses HTTP 402 but adds session-based billing instead of settling each request onchain. According to the article, it has supported x402 payments since June 2026.

The article says it is an open question whether the transaction counts reflect steady commerce.