H2O (web server)

H2O

Original author(s)	Kazuho Oku DeNA
Initial release	February 18, 2015 (2015-02-18)
Stable release	2.2.6 / August 13, 2019 (2019-08-13)
Written in	C
Operating system	Unix-like
Type	Web server
License	MIT License

H2O is a free and open-source web server software.

It is written in C, and is distributed under the terms of the MIT License.

Overview

It is designed on the presence of HTTP/2 and TLS, and maximizing the use of HTTP/2 technologies such as prioritization and server push, it achieves significantly better performance than conventional web server software such as nginx.

Features

H2O has the following key features:

• HTTP/1.0 and HTTP/1.1 support
• HTTP/2 support
  • Full support for dependency and weight-based prioritization with server-side tweaks
  • Cache-aware server push
• HTTP/3 support (experimental)
• TCP Fast Open
• TLS support
  • Session resumption (standalone and memcached)
  • Session tickets with automatic key rollover
  • Automatic OCSP stapling
  • Forward secrecy and fast AEAD cipher suite
  • Private key protection using privilege separation
• Static file serving
• FastCGI support
• Reverse proxy
• Scripting by mruby (Rack-based)
• Graceful restart and self-upgrade

History

In July 2014, Kazuho Oku started the development H2O as a mobile game server inside DeNA. The initial version was released in December 2014, and the first stable version was released in February 2015 when the HTTP/2 specification was finalized.

See also

• Fastly - The largest user of H2O in the world. Oku joined Fastly in January 2017.

External links

• h2o on GitHub