# Good Job, promise-based concurrency
[](https://travis-ci.org/dwrensha/gj)
[Documentation here](http://docs.capnproto-rust.org/gj/index.html).
EXPERIMENTAL! UNSTABLE! A WORK IN PROGRESS!
GJ is a port of the
[KJ concurrency framework](https://capnproto.org/cxxrpc.html#kj-concurrency-framework)
into Rust.
A GJ event loop allows you to execute many lightweight stackless tasks on a single operating system thread.
You can share mutable data between tasks without any need for mutexes or atomics.
GJ also provides a completion-based I/O interface.