> ## Documentation Index
> Fetch the complete documentation index at: https://docs.stateset.com/llms.txt
> Use this file to discover all available pages before exploring further.

# About the Universal Commerce Protocol

> Understand how UCP standardizes discovery and checkout.

# About the Universal Commerce Protocol

UCP standardizes discovery and checkout so commerce apps can interoperate across platforms.

## How UCP works

* Clients discover capabilities via `/.well-known/ucp`.
* A standard checkout session lifecycle is used across apps.
* Optional identity linking adds OAuth-based context.

## Why this design

UCP reduces custom integrations and makes checkout portable between systems.

## When to use UCP

* **Cross-platform commerce**: unify checkout behaviors
* **Marketplace apps**: standardize discovery and capabilities
* **Agent workflows**: predictable checkout flows

## Further reading

* [UCP Handler README](/stateset-ucp-handler/README)
* [UCP Integration Guide](/guides/universal-commerce-protocol-handler)