Docs · 17 Aug 2026 · Miven team
What is x402?
x402 is an open payment protocol that brings back the HTTP 402 status code for instant, automatic stablecoin payments over HTTP — designed for AI agents and pay-per-use APIs.
x402 revives HTTP 402 Payment Required, the long-dormant status code, as a working payment mechanism. Services monetize APIs and content onchain: a client (human developer or AI agent) pays programmatically for each request — without accounts, sessions, or recurring subscriptions.
Why it matters
AI agents and crawlers now consume large volumes of content and APIs, but there was no standard way to charge them. x402 gives publishers and API providers a protocol-level payment rail: when a bot hits a protected endpoint, the server responds with payment requirements, the bot pays with its wallet, and the content is delivered.
How the payment flow works
- Client sends a standard HTTP request to a protected endpoint.
- Server responds with
402 Payment Requiredplus payment instructions in thePAYMENT-REQUIREDheader. - Client creates a payment payload with its wallet.
- Client resubmits the request with a
PAYMENT-SIGNATUREheader. - Server verifies the payment via a facilitator and settles onchain.
- Server delivers the resource with a
200 OKresponse.
Payment schemes
- exact — fixed price, client signs for the advertised amount (EVM + Solana).
- upto — usage-based; client authorizes a maximum, server settles the actual amount via Permit2 (EVM).
- batch-settlement — payment channels: deposit once, sign off-chain vouchers per request (EVM).
x402 vs failed micropayment attempts
Earlier micropayment systems failed because they added friction: prepaid wallets, merchant accounts, or complex SDKs. x402 is different because it is native to HTTP — a client pays with the same request it already sends, using an EIP-3009 gasless signature. No registration, no approval flow, no account. That is why it works for machine-to-machine payments where humans would never complete a checkout.
Miven builds on x402 to power Pay-per-Crawl for AI bots and Pay-per-View for content. See also our comparison: Pay-Per-Crawl vs Pay-Per-View.
Frequently asked questions
What is x402?
x402 is an open payment protocol developed by Coinbase that revives the HTTP 402 Payment Required status code for instant, automatic stablecoin payments directly over HTTP. Clients — humans or AI agents — pay programmatically without accounts, sessions, or complex auth.
How does the x402 payment flow work?
The client sends a standard HTTP request. The server responds with 402 Payment Required and payment instructions in the PAYMENT-REQUIRED header. The client signs a payment using their wallet and resubmits the request with a PAYMENT-SIGNATURE header. The server verifies the payment via a facilitator, settles onchain, and delivers the resource with a 200 response.
Who is x402 for?
Sellers — service providers monetizing APIs or content — and buyers — developers and AI agents accessing paid services without manual payment flows.
Which networks does x402 support?
x402 v2 uses CAIP-2 network identifiers and supports Base, Polygon, Arbitrum One, World, Ethereum, and Solana. USDC transfers use EIP-3009 gasless transfers.
How is x402 different from subscriptions?
x402 replaces recurring subscription models with lightweight per-request micropayments. You pay exactly for what you consume — each API call or piece of content — instead of a flat monthly fee. It is also how AI agents can pay for content they crawl.