[[introduction]]
== Introduction

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

Cowboy aims to provide a complete HTTP stack, including its derivatives
SPDY, Websocket and REST. Cowboy currently supports HTTP/1.0, HTTP/1.1,
Websocket (all implemented drafts + standard) and Webmachine-based REST.

Cowboy is a high quality project. It has a small code base, is very
efficient (both in latency and memory use) and can easily be embedded
in another application.

Cowboy is clean Erlang code. It includes hundreds of tests and its code
is fully compliant with the Dialyzer. It is also well documented and
features both a Function Reference and a User Guide.

=== Prerequisites

Beginner Erlang knowledge is recommended for reading this guide.

Knowledge of the HTTP protocol is recommended but not required, as it
will be detailed throughout the guide.

=== Supported platforms

Cowboy is tested and supported on Linux.

Cowboy has been reported to work on other platforms, but we make no
guarantee that the experience will be safe and smooth. You are advised
to perform the necessary testing and security audits prior to deploying
on other platforms.

Cowboy is developed for Erlang/OTP 17.0, 17.1.2 and 17.3. By the time
this branch gets released the target version will probably be 18.0 and
above.

Cowboy may be compiled on other Erlang versions with small source code
modifications but there is no guarantee that it will work as expected.

Cowboy uses the maps data type which was introduced in Erlang 17.0.

=== Versioning

Cowboy uses http://semver.org/[Semantic Versioning 2.0.0].

=== Conventions

In the HTTP protocol, the method name is case sensitive. All standard
method names are uppercase.

Header names are case insensitive. Cowboy converts all the request
header names to lowercase, and expects your application to provide
lowercase header names in the response.

The same applies to any other case insensitive value.
