This would be a great integration for agencies serving professional services clients like law firms. Affinipay is the most popular payment processor for law firms (branded as LawPay) -- waaay more popular than Stripe. Affinipay also processes payments for health care professionals (branded as MedPay), accountants (branded as CPA Charge), other professionals (branded as ClientPay), and nonprofits (branded as Affinipay for Associations). Here is a link to their API documentation: https://developers.affinipay.com/reference/api.html