eBay announced that on January 1, 2023, the eBay app on Shopify is scheduled to be discontinued. The decision does not come as a big surprise. The app has a low ranking from users, and reviews show it was failing with functionalities such as inventory synchronization. eBay encourages sellers to switch to 3rd party software providers, such as GeekSeller if they wish to keep their Shopify and eBay in sync.
The eBay app will continue to function as normal through December 31, 2022. After that date, your existing listings on eBay will remain live and your sales will continue. To manage your listings and orders, you can simply go to the eBay website directly.
From the official eBay announcment