You are missing an OsCommerce shopping cart integration. Although not as popular as many of the "name brand" carts - OsCommerce is one of the oldest and most used carts in the world. Unfortunatley I will not be able to use ShipStation :(
Thanks for bringing this up! We’ll keep this in mind but would like to see more interest from other users before we pursue a partnership. If you know any other users that are interested please send them here!
As developing a seamless integration typically requires cooperation from both parties, we recommend reaching out to OsCommerce and expressing your interest in an integration to help expedite this process.
Scott Bradley Flour Confections commented
Thank you for the update. OsCommerce is an open source software - so I would recommend joining the OsC community forums to connect with those at OsC that can help with the integration... https://forums.oscommerce.com/forum.
The most current version code base can be found here: https://github.com/gburton/Responsive-osCommerce
Your developers will find OsCommerce and Zencart (which you do offer an integration for) to be of a very similar structure (some would call them almost identical).
The next version 2.4 is being developed here https://github.com/osCommerce/oscommerce2
Feel free to remove the links in fear of spam.... but do pass on the info.