Ask HN: Web-based Accounting System w/ API?

I'm looking to upgrade my accounting from the Excel and hand-build web-based system that I have been using.

I think its time to get a good, professional solution.

However, my business mostly makes sales online with Clickbank and PayPal and I don't want to have to manually input all of those sales.

Is there a web-based accounting system that has an API I can integrate with? That way I can have a script that automatically ads all my online sales into the system when they happen.

Thanks for any suggestions!