I think they may have been company run by somebody in Ukraine, for some reason because their site had a blue yellow flag. The site was a rip off of SellBrite but it was done way way better and very smooth and although it did have bugs, it was functional in a way that I could only wish about when I look at SellBrite which hasn't been really updated for 10 years at minimum (GoDaddy doesn't spent money on it but why did they acquire it then??) Anyhow SellBrite was very promising site but they also had integration with Ebay, maybe some other sites, I believe Shopify. I used them mainly for Etsy because there aren't many tools that support Etsy, given that they don't have a published API in the way as Ebay does. What they have done way better is the templates and shipping policies and also upload CSV is way better than SellBrite. So since they have gone dark, I am back at Sellbrite for Etsy at least, but may use them for Ebay too. I know there are plenty of 3rd party cross listing tools but to be able to import export via CSV, there aren't that many options and Sellbrite is pretty decent and decent price plans with free tier as well. SellerSkills was a ripoff of SellBrite because the page logic was exactly same but much better UI. Maybe SellBrite GoDaddy did sue them or maybe they sold side to somebody else and gone offline? Their social media also gone dead https://www.facebook.com/SellerSkills/ and their support email also comes back undeliverable. This is archived website: https://web.archive.org/web/20250424173316/https://sellerskills.com/ Alternatively I may look at https://base.com/en-GB/home/ , they have plenty of integrations, offer a very free price plan too and are quite robust and seem to support shipping policies well.
