SpreadSimple - A blazing-fast way to create and manage sites using Google Spreadsheets
CALCONIC_ - Build & add interactive calculators to your website! Choose from more than 50 premade calculators or build your own from scratch. No coding required. Free plan available. Zapier Integration. Publish Anywhere.
Algo by AirDev - Turn a Google Sheet model into a web app in 5 minutes
ConvertCalculator - Create powerful, beautiful Calculator forms
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
Calcapp - Build apps instead of spreadsheets