A Fast, Concurrent Web Server for Ruby & Rack

Speed & Concurrency

Current Release: 6.5.0

Unlike other Ruby Webservers, Puma was built for speed and parallelism. Puma is a small library that provides a very fast and concurrent HTTP 1.1 server for Ruby web applications. It is designed for running Rack apps only.

What makes Puma so fast is the careful use of a Ragel extension to provide fast, accurate HTTP 1.1 protocol parsing. This makes the server scream without too many portability issues.

Quickstart with Bundler

If you are using Bundler, just add Puma to your project's Gemfile:

gem "puma"

Once you've installed your bundle, start Puma by running:

bundle exec puma

Quickstart without Bundler

If you are not using Bundler, you can install Puma directly from the command line:

gem install puma

Once installed, start Puma by running:

puma

Resources

Puma Vs. Other Webservers

Memory Usage Comparison (Showing memory usage over time - less is better)

Puma - 78 Mb
Rainbows! (1x16) - 120 Mb
Unicorn - 1076 Mb
Rainbows! (16x32) - 1138 Mb

Speed Comparison (Requests per second plotted against the number of concurrent requests - more is better)

	1	2	3	4	5	10	20	30	40	50
Puma (16:16)	3264	6575	8969	9923	9925	9693	9482	9306	9341	9219
Puma (16:16, KA)	4589	8849	12245	14601	15909	14419	12939	12564	12701	12538
Rainbows! (1x16)	673	1161	1486	1730	1949	1814	778	782	727	710
Rainbows! (1x16, KA)	775	1336	1715	2006	2271	2085	732	1092	634	315
Unicorn	557	1054	1535	2032	2450	3958	5329	9330	8938	5235
Unicorn (KA)	554	1031	1517	1967	2457	3938	5292	9727	8985	9298
Rainbows! (16x32)	583	1150	1675	2173	2667	3152	3345	3384	3324	3417
Rainbows! (16x32, KA)	760	1479	2200	2853	3464	5413	7320	7350	7273	6419

Notes:

The KA entries are the benchmark run with the client doing keepalive requests.

Puma History

Puma comes from a long line of ruby webservers derived from Zed Shaw's seminal work on Mongrel. The primary element that remains is Mongrel's great HTTP parser written in ragel and executed in either C or Java, depending on the ruby implementation.

Evan Phoenix looked at Mongrel and saw a chance to take the idea and move it forward to incorporate two elements absent from the original work. Firstly, the Ruby world has moved almost entirely to using Rack as the primary interface for web apps. Mongrel was written in a pre-Rack world, so the first thing Puma did was cut out all the unnecessary abstractions and support the Rack interface directly. Second, Puma is designed to be used on a Ruby implementation which provides true parallelism, such as Rubinius and JRuby. Tuning for the capability and patterns that these implementations provide meant rethinking how requests entered the system and were handled. Incorporating these ideas, Puma was born from Mongrel and began moving forward.

Today, Puma runs on all Ruby implementations, but will always run best on any implementation that provides true parallelism. It looks to provide a simple and high performance request/response pipeline to Rack apps, allowing it to be used by nearly all ruby web applications.

Created By

Puma was created by Evan Phoenix in late 2011 as a derivative of Mongrel. Now, most of the original Mongrel code has been rewritten except for the parser. The git history for the project provides a timeline of the evolution of the project.