Dashblock - Turn any website into an API
Stripe - Online payment processing for internet businesses. Stripe is a suite of payment APIs that powers commerce for online businesses of all sizes. Use Stripe’s payment platform to accept and process payments online for easy-to-use commerce solutions.
Sheety - Turn any Google sheet into an API instantly, for free. Power websites, apps, or whatever you like, all from a spreadsheet. Changes to your spreadsheet update your API in realtime. Neat
TrueLayer - Simple Bank APIs to access real-time financial data
Postman - The Collaboration Platform for API Development
Teller API - A single API to connect your app with any bank's account