Any invoicing/billing/credit card processing outfits with an API?

I have built a custom client portal for my eviction practice that automates intake, doc production, etc. I can do just about everything in the portal that I do in Clio, except invoicing and credit card processing. My goal is to leave Clio completely, but I need to find a way to invoice clients and process credit card payments similarly to Clio. Im hanging onto Clio for that alone as I can push matters into it, enter the fee, and use it to bill at the end of the month. Researching LawPay, etc, there doesn’t seem to be anyone offering this as a stand alone with an API. If anyone is aware of anything that would work, I’m all ears. Thanks!