Small, fast, modern HTTP server for Erlang/OTP.
Erlang Other
Latest commit 8fe700f Oct 18, 2016 @essen essen Erlang/OTP 19.1.5



Cowboy is a small, fast and modern HTTP server for Erlang/OTP.


Cowboy aims to provide a complete HTTP stack in a small code base. It is optimized for low latency and low memory usage, in part because it uses binary strings.

Cowboy provides routing capabilities, selectively dispatching requests to handlers written in Erlang.

Because it uses Ranch for managing connections, Cowboy can easily be embedded in any other application.

Cowboy is clean and well tested Erlang code.


The project is currently sponsored by Sameroom.

The original SPDY implementation was sponsored by LeoFS Cloud Storage. It has since been superseded by HTTP/2.

Online documentation

Offline documentation

  • While still online, run make docs

  • User guide available in doc/ in PDF and HTML formats

  • Function reference man pages available in doc/man3/ and doc/man7/

  • Run make install-docs to install man pages on your system

  • Full documentation in Asciidoc available in doc/src/

  • Examples available in examples/

Getting help