T3 vs Zepto: What are the differences?

Developers describe T3 as "Client-side JavaScript framework for building large-scale web applications, created by Box". T3 is different than most JavaScript frameworks. It's meant to be a small piece of an overall architecture that allows you to build scalable client-side code. T3 is explicitly not an MVC framework. It's a framework that allows the creation of loosely-coupled components while letting you decide what other pieces you need for your web application. You can use T3 with other frameworks like Backbone or React, or you can use T3 by itself. On the other hand, Zepto is detailed as "Minimalist JavaScript library for modern browsers, with a jQuery-compatible API". While 100% jQuery coverage is not a design goal, the APIs provided match their jQuery counterparts. The goal is to have a ~5-10k modular library that downloads and executes fast, with a familiar and versatile API, so you can concentrate on getting stuff done.

T3 and Zepto can be categorized as "Javascript UI Libraries" tools.

T3 and Zepto are both open source tools. It seems that Zepto with 14.5K GitHub stars and 4.06K forks on GitHub has more adoption than T3 with 1.59K GitHub stars and 160 GitHub forks.