SpreadsheetDB vs Tabletop.js: What are the differences?

SpreadsheetDB: A database that you can query with spreadsheets. SpreadsheetDB is a DBaaS (database as a service). It can be queried with an API over HTTP to insert records and to manipulate JSON spreadsheets; Tabletop.js: Tabletop.js takes a Google Spreadsheet and makes it easily accessible through JavaScript. Tabletop.js easily integrates Google Spreadsheets with Backbone.js, Handlebars, and anything else that is hip and cool. It will also help you make new friends and play jazz piano.

SpreadsheetDB and Tabletop.js can be primarily classified as "Spreadsheets as a Backend" tools.

Tabletop.js is an open source tool with 3.07K GitHub stars and 390 GitHub forks. Here's a link to Tabletop.js's open source repository on GitHub.