Hi Everyone.
I represent Parex. We have an app which is very similar to OneSaas and we are getting customers to use our system for Xero. Please find further details at https://apps.parextech.com/
We are well rated on Xero apps section and Shopify/Wix platforms as well. We are working with Squarespace team to get us listed on their site but for now they allow only limited apps to list on their apps page.
Happy to answer questions for anyone.
Thanks,
Parex Team