CalcFusion - CalcFusion enables users to transform Spreadsheets into APIs that can be plugged into any IT system.
Stein - Use Google Sheets as your no-setup database
Sheetbase - Free, fast and fun way to build modern websites and apps 🛠️
Sheetson - Instantly turn any Google Sheet into RESTful API
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
Sheetsu - Turn Google Spreadsheet into API