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ninenines/cowboy

Cowboy is an Erlang-based HTTP server that provides a comprehensive framework for building web applications and services. It supports modern protocols including HTTP/1.1, HTTP/2, HTTP/3, and WebTransport, while also offering built-in capabilities for WebSocket communication and Server-Sent Events. The system includes features for automatic response compression, file serving, and middleware-based request processing, all supported by a robust test suite and extensive documentation.

60.5

Adequate · 5 August 2026

13k

lines of production code

Erlang

primary language

1

bus factor · 153 authors in all

5

measurements over time

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How it got here

2011–2012 · HTTP/2 and compression features

This period focused on enhancing the HTTP/2 protocol support and introducing automatic response body compression via a new stream handler. The project also expanded its example suite to demonstrate chunked transfer encoding, POST echo services, and secure HTTP/2 servers, while simultaneously modernizing the build system and documentation infrastructure.

7 changes

2013 · expansion of example applications

This period focused on expanding the project's example suite with new demonstrations for WebSocket, Server-Sent Events, and Markdown middleware. Several existing examples were refactored into standalone releases using relx, improving their buildability and self-containment.

6 changes

2014–2016 · HTTP/3 and WebTransport support

This period focused on expanding Cowboy's protocol support by adding HTTP/3 and WebTransport capabilities, alongside new stream handlers for compression and metrics. The team also modernized the documentation infrastructure by converting guides to Asciidoc and added new examples for file serving and multipart uploads.

7 changes

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About this page

  • The description of this project is derived from its own commit history, not from its README.
  • The score is its highest published measurement, taken on 5 August 2026 at a pinned commit. It is not a live figure and does not change until the project is measured again.
  • Measured at commit 702edc6d75 — the exact code this score is about.
  • Scored under rubric rubric-2026.08.19. Score the same commit under that rubric and you get the same number.
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