POEditor - The translation and localization management platform that's easy to use *and* affordable!
Mustache.js - Minimal templating with {{mustaches}} in JavaScript - janl/mustache.js
Weblate - Weblate is a free web-based translation management system.
EJS - An open source JavaScript Template library.
Crowdin - Localize your product in a seamless way
FLAVE - Flave was created to bring ASP.