Blog Posts

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Enter x402: The Web’s Native Payment Protocol
HTTP has always had a status code for payments: 402 Payment Required. It was reserved in 1999 but never standardized. Until now.

The x402 protocol finally gives meaning to that status code:

Client requests a resource
Server responds with 402 and payment requirements
Client signs a payment authorization locally
Server verifies and settles the payment
Client gets access to the resource
No redirects. No checkout flows. No human intervention. Just HTTP.

Nevermined’s Programmable Extension: nvm:erc4337
Standard x402 handles simple “pay X tokens for this request” flows. But AI agents need more:

Subscription models: “This agent is on our enterprise plan”
Credit systems: “Deduct 5 credits from my balance”
Usage caps: “Don’t let me spend more than $100 today”
Delegated payments: “My company’s smart account pays, not me personally”
That’s why we built the nvm:erc4337 scheme—an extension that makes x402 programmable.

From: Blog Posts.

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