x402
Open protocol for paying per request over HTTP 402, used by AI agents to pay APIs in stablecoins
x402 is an open standard for paying over HTTP. A server answers a request with 402 Payment Required and its price; the client pays (usually in USDC) and retries with proof of payment. The buyer needs no account or API key with the seller, which suits AI agents calling paid APIs.
The spec and SDKs are Apache-2.0, governed by the x402 Foundation at the Linux Foundation since July 2026. Settlement runs through a facilitator: Coinbase's is free for the first 1,000 onchain transactions a month, then $0.001 each. Payments are final, with no chargebacks.
Pricing: Free
Choosing a payments layer for agents right now?
One click, anonymous. Helps us know our visitors.
Thanks, that helps.
Choosing a payments layer for agents right now?
One click, anonymous. Helps us know our visitors.
Thanks, that helps.
x402 Alternatives
Explore 81 products in the Agents category. View all x402 alternatives.
Openspender
Payment router for AI agents: pay per request across LLM APIs and tools from a self-custodial wallet
Anyway
Agent wallets with server-side spending caps that pay for APIs per call over x402
MPP (Machine Payments Protocol)
Open HTTP 402 payment protocol from Stripe and Tempo, extensible to stablecoins, cards and Lightning
PromptLeo
No-code AI digital employees (Support, SDR, Research, Ops) built on open agent models, EU-hosted
Superagent
Prototype and deploy agents powered by large language models.
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