那么Cowboy是什么呢？
Cowboy is a small, fast and modular HTTP server written in Erlang.
其定位非常明确：
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.
目前还支持websocket和spdy协议(由leofs赞助），是个完整的http协议栈实现，功能强劲。由于是最近才发展起来的，充分考虑了性能，强调代码的整洁，作者在产品层面对erlang的优缺点非常了解，实现的很优雅很高效。 目前多个项目都是用它支撑的，也反过来刺激它走的很稳很快，代码维护也很活跃，比如竞争对手misultin感觉没有超越的希望就放弃了。
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more: http://blog.yufeng.info/archives/3051