https://t.me/intgstorebot
(source: https://github.com/r3-dev/telegram-marketplace-miniapp/commit/79ab86d8eae8632d161f44557c6eb1d3b1dcb6c5)

This is the marketplace for telegram project. It provides dashboard for sellers and storefront for customers.

Great idea! I'd suggest you add a background to buttons as they're not really standing out as buttons. Also, items don't seem to get added into the marketplace.