TL,DR: Node, Erlang, React, Flocks.JS, MySQL, and CloudFront.

For the frontend, I am writing a routable, cached SPA in React and d3, orchestrated with Flocks, stored in S3 and fronted with CloudFront, generated by Node, backed with MySQL (because it has semi-mature clustering.)

For the backend, I use a custom Erlang stack built on htstub and emysql.

The build process is orchestrated with gulp, uses eslint, vows, karma, and jsverify for testing, travis ci for CI/CD, and deploys automatically on full test passing. (I have extensive test coverage.)

I can use remarkably few tools to get the results I want. I am happy with the stack.

I have an alternative approach to handling multiple interfaces, as a replacement for responsive. I don't use media queries to do that. Instead I have a top level React layout control, and which top level control is invoked is based on the client. The same goal is suited, but it isn't jury rigged through CSS.

C++ backend, pure javascript (with some emscripten) front-end for the web conferencing platform I work on. Mysql/perl/php for the website, with Centos 6 on the server.

I'm more interested in building a very efficient and reliable service and solving challenging problems than using trendy technologies.