dashdash is the spreadsheet with the best data and APIs for business.
It's the easiest way to access online services and build automated tools using the spreadsheet skills you already have.
Keikai is designed and architected for big data. With frame-based rendering and super light-weight data structure, it is the fastest web spreadsheet regardless of size.
TotalSheets is a platform that offers you all the tools you need to create a fully functional online spreadsheet. Similar to Google Sheets in concept, but with the intention to give a greater control to owners over the appearance of their published spreadsheets.