Fabio’s most requested feature is to be able to upload a Price List Item catalog (sometimes requested as a “Product Catalog”). Even FreeAgent support has asked us if Fabio can support it! 
It’s basically a new endpoint with the following attributes:
Quantity - Decimal
Item_Type - String
Description - String
Price - Decimal
Sales_Tax_Rate - Decimal
Code - String
Can you put this on your wish list - preferably at the top 
You’re in luck! We implemented this recently and hadn’t updated the documentation yet, so I’m sorting that out.
Edit: see our price list items API documentation, which is now up to date
For UK companies, you’ll want to set vat_status rather than the sales tax rate as VAT rates vary over time and this allows the price list to work independently of date.
I hope that helps.
Cheers,
Dominic
Hallelujah! Thanks. 
No problem! We’ve now published the API documentation over at Price List Items.
Cheers,
Dominic
And we’ve now launched the corresponding update to Fabio.