x402: how AI agents
pay for the internet.
x402 revives the dormant HTTP 402 Payment Required status so any API can charge an AI agent a stablecoin micro-fee per request — no accounts, no cards, settled in under two seconds. This is the tracker for the standard that could meter the agent economy.
Compiled from public 2026 reporting (Solana, Keyrock, Coinbase). See /api/x402.json.
The 402 handshake, in four steps
A single automated round-trip turns "pay me" into "paid" — with the agent as the customer.
Request
An agent calls a paid API endpoint with no payment attached.
402 + terms
The server replies 402 with a machine-readable price and payment spec (asset, amount, address).
Pay
The agent signs a USDC micropayment on-chain (default: Base) and attaches the receipt.
Deliver
The server verifies via a facilitator and returns the resource. Total time: sub-2s.
Who's shipping x402
The standard went from a May-2025 idea to a Linux Foundation project with the whole payments industry attached.
| Player | Role in x402 | Status |
|---|---|---|
| x402 Foundation (Linux Foundation) | Neutral home for the protocol; Coinbase donated the spec. | Live |
| Coinbase CDP | Original author; Bazaar directory of 10k+ payable tools. | Live |
| Solana | High-throughput chain for x402; tens of millions of txns. | Live |
| Cloudflare | x402 in the Agents platform + pay-per-crawl for bot access. | Live |
| Apify | 20k+ automation Actors made payable over x402. | Live |
| AWS | Bedrock AgentCore Payments; CloudFront machine-readable pricing. | Preview |
| Fireblocks | Joined the x402 Foundation; agentic payments suite. | Live |
| Backers | Stripe, Visa, Mastercard, Amex, Shopify, Google, Microsoft. | Aligned |
x402 vs AP2 vs ACP
Three standards, three jobs. They increasingly stack rather than compete.
| x402 | AP2 (Google) | ACP (Stripe/OpenAI) | |
|---|---|---|---|
| Core job | Per-request payment for APIs/tools | Authorization & mandates for agent spend | Consumer checkout inside assistants |
| Settles in | USDC (on-chain) | Rail-agnostic | Cards / stablecoin |
| Best for | Machine-to-machine micropayments | "Agent may spend ≤$X" proofs | Buying products via chat |
| Openness | Open / LF-governed | Open spec | Open spec |
| Maturity | Live at scale | Emerging | Emerging |
Our read of public specs and reporting, not endorsements. Corrections: submit here.
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