Wren-nest, or wren’s nest, is like a jsFiddle for wren code. You can write, import, and save your scripts online. It’s built using Github’s Gist API, allowing you to pull in Gists and generate permlinks for whatever you write. Open source, and mobile friendly. It’s written in Dart.
It's a useful tool, as the wren VM needs to be compiled before use, and newer programmers may not know how to do that on their systems. Unfortunately, this application is not updated as often as the VM it's based on.
I started this project in order to build some familiarity with c, as well as emscripten.