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Small, fast, modular HTTP server written in Erlang.
Erlang Other


Cowboy is a small, fast and modular HTTP server written in Erlang.


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.

No parameterized module. No process dictionary. Clean Erlang code.


The project is currently sponsored by

The SPDY implementation was sponsored by LeoFS Cloud Storage.

Online documentation

Offline documentation

  • While still online, run make docs
  • 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 Markdown available in doc/markdown/
  • Examples available in examples/

Getting help

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