Google announced UCP (Universal Commerce Protocol) two days ago. I realized developers building AI shopping agents have no real merchant to test against, so I built one.

  Live sandbox: https://puddingheroes.com/api/ucp/

  What you can do:
  - Discovery endpoint at /.well-known/ucp.json
  - Browse 9 products (books, vacation rental, memberships, experiences)
  - Complete fake checkouts with payment_token: "sandbox_test"
  - Get a real PDF download for the free item (not a mock)

  curl https://puddingheroes.com/api/ucp/test

  The products are from my actual business (sci-fi novel, Airbnb property, community membership) so it's realistic test data, not lorem ipsum.

  GitHub: https://github.com/steven2030/ucp-merchant

  Built with Flask. MIT licensed. PRs welcome.