Stitch’s frontend is used to configure data sources and destinations and monitor the status of each. Although we have been using AngularJS since its early days, we recently introduced React components into our front end, which many of our developers find easier to work with. We started using CoffeeScript when it was one of the few options for a more expressive alternative to vanilla JavaScript, but today we opt to instead write new code in ES6, which we feel is a more mature alternative.