# 7.3 The x402 Protocol Stack

The x402 protocol serves as the economic layer of the internet for machine intelligence.\
It extends the HTTP standard with native payment requirements, allowing Agents to monetize access natively at the protocol level.

Each transaction includes:

* Header Metadata: defines pricing model, payment currency, and proof format.
* Settlement Flow: 402 challenge → payment submission → header verification → response.
* Security Envelope: cryptographic signatures ensure authenticity of payer and provider.

This transforms simple API calls into verifiable economic interactions, bridging the gap between computation and commerce.


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