Apigee - Intelligent and complete API platform
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
Apiary - Collaborative design, instant API mock, generated documentation, integrated code samples, debugging and automated testing
SheetBest - Turn a Google SpreadSheet into a JSON Database API
Postman - The Collaboration Platform for API Development
Dashblock - Turn any website into an API