H2O is an optimized HTTP server implementation that can be used either as a standalone server or a library.

• HTTP/1.0 (http and https)
• HTTP/1.1 (http and https)
• Websocket (RFC6455, both ws and wss)
• HTTP/2.0 (draft 14, via Upgrade, NPN, ALPN)

• OpenSSL (mandatory)
• libyaml (optional; required when building the server)
• libuv 1.0.0 (optional; required when using h2o as a library)
• wslay (optional; required if you need support for websocket)

Written from the ground up, H2O outperforms nginx by more than 2x. The table below is a comparison of request-per-seconds taken using ab -c 500 -n 100000 -k on Ubuntu 14.04 running on VMWare Fusion.

Run the commands below to build and run the H2O server. The last command will read the configuration from examples/h2o.conf and start listening on port 8080. Try accessing http://127.0.0.1:8080/.

$ git submodule update --init --recursive
$ cmake .
$ make h2o
$ ./h2o -c examples/h2o.conf

$ git submodule update --init --recursive
$ cmake .
$ make libh2o

The library is designed to work together with the upcoming libuv version 1.0.0. Examples can be found within the examples/ directory.