Puma VS Rack

Compare Puma vs Rack and see what are their differences.


A Ruby/Rack web server built for parallelism (by puma)


A modular Ruby web server interface. (by rack)
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Puma Rack
40 23
7,600 4,842
0.3% 0.4%
8.7 7.4
7 days ago 9 days ago
Ruby Ruby
BSD 3-clause "New" or "Revised" License MIT License
The number of mentions indicates the total number of mentions that we've tracked plus the number of user suggested alternatives.
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.


Posts with mentions or reviews of Puma. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2024-02-21.
  • Breaking the 300 barrier
    3 projects | dev.to | 21 Feb 2024
    As we use Puma as our webserver for our rails application, I quickly went to Puma's config file which typically resides in config/puma.rb. The config was set as
  • Would you consider Rails as stable nowadays ?
    2 projects | /r/rails | 8 Dec 2023
    They do! It's in the first section of the readme on the repo:
  • Hosting Rails App on AWS
    2 projects | /r/rails | 27 Jun 2023
    Start with service with systemd
  • Recommended way to implement Puma plugin configuration
    1 project | /r/ruby | 2 Jun 2023
  • Could not detect rake tasks
    6 projects | /r/rails | 3 May 2023
    # Use the Puma web server [https://github.com/puma/puma] gem "puma", "~> 5.0" # Build JSON APIs with ease [https://github.com/rails/jbuilder] # gem "jbuilder" gem 'rack-cors' gem "devise" gem "jsonapi-serializer" gem 'devise-jwt' gem 'active_model_serializers' gem 'followability' gem 'dotenv-rails', groups: [:development, :test, :production] gem 'sprockets' # Use Redis adapter to run Action Cable in production # gem "redis", "~> 4.0" # Use Kredis to get higher-level data types in Redis [https://github.com/rails/kredis] # gem "kredis" # Use Active Model has_secure_password [https://guides.rubyonrails.org/active_model_basics.html#securepassword] # gem "bcrypt", "~> 3.1.7" # Windows does not include zoneinfo files, so bundle the tzinfo-data gem gem "tzinfo-data", platforms: %i[ mingw mswin x64_mingw jruby ] # Reduces boot times through caching; required in config/boot.rb gem "bootsnap", require: false # Use Active Storage variants [https://guides.rubyonrails.org/active_storage_overview.html#transforming-images] # gem "image_processing", "~> 1.2" # Use Rack CORS for handling Cross-Origin Resource Sharing (CORS), making cross-origin AJAX possible # gem "rack-cors" group :development, :test do # See https://guides.rubyonrails.org/debugging_rails_applications.html#debugging-with-the-debug-gem gem "debug", platforms: %i[ mri mingw x64_mingw ] end group :development do gem "sqlite3", "~> 1.4" # Speed up commands on slow machines / big apps [https://github.com/rails/spring] # gem "spring" end group :production do gem 'pg' end
  • Dusting off my rails knowledge, need some tips / guidance on rails 7 and production
    10 projects | /r/rails | 7 Apr 2023
    source "https://rubygems.org" git_source(:github) { |repo| "https://github.com/#{repo}.git" } ruby "3.1.0" # Bundle edge Rails instead: gem "rails", github: "rails/rails", branch: "main" gem "rails", "~> 7.0.4", ">=" # The original asset pipeline for Rails [https://github.com/rails/sprockets-rails] gem "sprockets-rails" # Use sqlite3 as the database for Active Record gem "sqlite3", "~> 1.4" # Use the Puma web server [https://github.com/puma/puma] gem "puma", "~> 5.0" # Use JavaScript with ESM import maps [https://github.com/rails/importmap-rails] gem "importmap-rails" # Hotwire's SPA-like page accelerator [https://turbo.hotwired.dev] gem "turbo-rails" # Hotwire's modest JavaScript framework [https://stimulus.hotwired.dev] gem "stimulus-rails" # Build JSON APIs with ease [https://github.com/rails/jbuilder] gem "jbuilder" gem "mongoid" gem "mongoid-grid_fs" gem 'bootstrap', '~> 5.2.2' #sourced from https://github.com/twbs/bootstrap-rubygem gem 'rack-cors' # Windows does not include zoneinfo files, so bundle the tzinfo-data gem gem "tzinfo-data", platforms: %i[ mingw mswin x64_mingw jruby ] # Reduces boot times through caching; required in config/boot.rb gem "bootsnap", require: false
  • Write your own Domain Specific Language in Ruby
    2 projects | dev.to | 6 Feb 2023
    That doesn't mean one excludes the other. Gems like Puma use the instance_eval method for their configuration file.
  • Welcome to Puma 6: Sunflower
    1 project | /r/hypeurls | 22 Oct 2022
    1 project | news.ycombinator.com | 22 Oct 2022
  • puma 6.0 released
    2 projects | /r/ruby | 21 Oct 2022
    Anyway I did it: https://github.com/puma/puma/issues/3003 It's quite more complicated: https://github.com/puma/puma/issues/2999 A fix is in progress: https://github.com/puma/puma/pull/3002


Posts with mentions or reviews of Rack. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2023-07-03.
  • Como desenvolvi um backend web em Clojure
    23 projects | dev.to | 3 Jul 2023
  • How to Use Sinatra to Build a Ruby Application
    8 projects | dev.to | 7 Jun 2023
    Because of its lightweight and Rack-based architecture, Sinatra is great for building APIs, mountable app engines, command-line tools, and simple apps like the one we'll build in this tutorial.
  • Building a Ruby app without any framework
    1 project | /r/ruby | 26 Apr 2023
    Since you mentioned Sinatra and Rails I assume you're talking about web apps. In that case you want to build a Rack Application. That's where web frameworks' responsibility ends.
  • Ask HN: Release Notes
    1 project | news.ycombinator.com | 9 Feb 2023
    I'm thinking about building a website that scrapes release notes from sources like https://community.ui.com/releases, https://github.com/rack/rack/blob/main/CHANGELOG.md, https://developer.android.com/about/versions/13/release-notes etc, and cleans them up & formats into the same format so they can be searched a lot easier.

    It seems like the best place to start would be for folks who read HN since we refer to these quite a bit day-to-day to figure out what changes in software, apps, etc. Let's open this up with a few questions:

    1. Would you find a service like this useful? Why or why not?

    2. What release notes would you want to have formatted into the same thing and why?

    3. What features or capabilities would you like to see a service like this do? e.g. would you like to select multiple "products/apps/whatever" and see their release notes in one timeline? Side-by-side? etc. etc. etc.

  • Elixir Plugs
    1 project | dev.to | 2 Dec 2022
    In Elixir world, Plug is a bit similar to Rack in Ruby. Official documentation describes Plug as:
  • Rack 3 Upgrade Guide
    1 project | news.ycombinator.com | 22 Oct 2022
  • Newb here: have you written your own web server? Seeking advice
    13 projects | /r/ruby | 18 Jun 2022
    The spec for Ruby's Rack is another good reference for how a Ruby webserver is expected to work.
  • The Definitive Guide to Rack for Ruby and Rails Developers
    4 projects | dev.to | 24 May 2022
    You've been around in the Rails world for a while. You know your way around rails. But you keep hearing this word 'Rack' and don't really understand what it is or what it does for you. You try to read the documentation on the Rack Github repository or the Rails on Rack guides, but the only thing it does is add to the confusion.
  • Crafting mini RubyOnRails
    2 projects | dev.to | 10 May 2022
    Begin with writing a rack-middleware. Rack is a standard library for writing a web server. The main structure is simple. Here is an example:
  • Request Coalescing in Async Rust
    4 projects | news.ycombinator.com | 6 Mar 2022
    Coming from the Ruby ecosystem, a lot of this played out similarly to how the Rack[1] middleware conventions developed in the early Rails v1 and v2 days. Prior to Rack there was a lot of fragmentation in HTTP server libraries, post-Rack everything more or less played nicely as long as libraries implemented Rack interfaces.

    I don't write Rust professionally, but it was a bummer seeing that this seems to be a place that was figured out (painfully) in ecosystems used heavily for web development--Javascript and Elixir have their own Rack equivalents[2][3]. I hope that Tower plays a similar role to unify the library ecosystem in Rust.

    1. https://github.com/rack/rack

    2. http://expressjs.com/en/guide/writing-middleware.html

    3. https://github.com/elixir-plug/plug

What are some alternatives?

When comparing Puma and Rack you can also consider the following projects:

Thin - A very fast & simple Ruby web server

Unicorn - Unofficial Unicorn Mirror.

falcon - A high-performance web server for Ruby, supporting HTTP/1, HTTP/2 and TLS.

Goliath - Goliath is a non-blocking Ruby web server framework

Phusion Passenger - A fast and robust web server and application server for Ruby, Python and Node.js

Iodine - iodine - HTTP / WebSockets Server for Ruby with Pub/Sub support

TorqueBox - TorqueBox Ruby Platform