You have a choice of many commercial plug-ins for Zen Cart which offer integration with eBay (and other marketplaces like Amazon and Wal-Mart). These tend to be expensive and many charge a fee per listing or sale. This is understandable because eBay integration is hard!
Making Zen Cart and eBay work together can be a challenge. This is mainly due to the number of options offered by eBay.
To reduce the challenge, my version of eBay Integration is mostly meant to satisfy our specific needs and not compete with the more complete solutions offered by others.
The initial version of my eBay Integration support for Zen Cart plug-in only works with the US version of eBay. Adding support for other countries shouldn’t be too difficult, but we only have an eBay store on the US site, so it is most important that we get that working first.
The other big limitation, at least for now, is that variations (size, color, etc.) won’t be handled. It’s not really the right way to do things, but we create separate products for each variation in Zen Cart and eBay.
A minor limitation will be that adding of products to eBay won’t be fully automated. The tool will create eBay listings from your Zen Cart products, but you will have to edit them (once!) in eBay before activating them in the tool. This is so that the tool doesn’t have to support all of the shipping options and business policies offered by eBay.
Finally, I am going to require you to get your own Developer Tokens for accessing eBay’s Application Program Interface (API). This saves me from having to get the plug-in approved by eBay while allowing you to update or modify it to support your specific needs.