Sheetsu - Turn Google Spreadsheet into 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
SpreadSimple - A blazing-fast way to create and manage sites using Google Spreadsheets
SheetBest - Turn a Google SpreadSheet into a JSON Database API
SheetAside - Access your Google Sheets from where you are
Dashblock - Turn any website into an API