# puma/puma

A Ruby/Rack web server built for parallelism

Repository: https://github.com/puma/puma
Canonical: https://ross.abutalabs.com/products/puma
Homepage: https://puma.io
Language: Ruby
License: BSD-3-Clause
License Family: permissive
Topics: ruby, server, multithreading, rack
Last push: 2026-08-25T01:03:09+00:00

## Health v2 (maintenance only)
Score: 95/100 (v2, computed 2026-09-03T02:39:23.370411+00:00)
- activity 99, release rhythm 86, longevity 100
- inputs: {"age_days": 5459, "days_push": 9, "days_rel": 99, "gap_med": 19, "n_releases_24m": 16}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 7914, forks 1489 (observed 2026-08-28T04:10:09.728556+00:00)

## What it is
Puma is a fast, multi-threaded and multi-process HTTP 1.1 web server for Ruby/Rack applications, featuring a C-optimized Ragel HTTP parser inherited from Mongrel. It is the most popular Ruby web server and the default for Ruby on Rails, supporting SSL, cluster mode with copy-on-write forking, and zero-downtime rolling restarts.

## Use cases
- serve a Ruby on Rails application in production
- run a Sinatra app with a fast concurrent server
- serve any Rack-based Ruby web application
- deploy a Ruby web server without a reverse proxy using built-in SSL and request buffering
- improve throughput of IO-bound Ruby apps via multi-threaded request handling
- run a Ruby web server in cluster mode with pre-forked worker processes
- perform zero-downtime rolling restarts of a Ruby web application

## When to choose
- you need a production-grade HTTP server for a Rack-compatible Ruby app (Rails, Sinatra, etc.)
- you want high concurrency through multi-threading and optional multi-process cluster mode
- you want the de facto standard Ruby web server with 15+ years of battle-tested parsing
- you need SSL, phased restarts, or standalone deployment without nginx in front

## When to avoid
- you are not building a Ruby/Rack application
- you need an async/evented server model rather than a thread pool (e.g., consider Falcon)
- you need HTTP/2 or HTTP/3 serving, which Puma does not provide

## Facets
- artifact type: library
- maturity: stable
- function: http-server, web-framework, concurrency, cli
- domain: web-development, backend, developer-tools
- platform: ruby, windows, cross-platform
- tags: rack, ruby-on-rails, sinatra, thread-pool, cluster-mode, ssl, zero-downtime-restarts, http1-1, linux, macos

## Member repositories
- puma/puma (main) score 95

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:09.728556+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:33:16.807124+00:00, confidence not recorded.
  - readme: https://github.com/puma/puma (fetched 2026-08-28T04:10:09.728556+00:00, sha 17f924fc30f0)
  - homepage: https://puma.io (fetched 2026-08-29T08:30:03.707386+00:00, sha 1ce8166d3784)
  - site_page: https://puma.io/puma4 (fetched 2026-08-29T08:30:03.729334+00:00, sha a2b3ecc0e9ec)
  - site_page: https://puma.io/puma (fetched 2026-08-29T08:30:03.716623+00:00, sha 24ff032d71c6)
  - site_page: https://puma.io/puma7 (fetched 2026-08-29T08:30:03.719638+00:00, sha 97ad8163e35b)
  - site_page: https://puma.io/puma6 (fetched 2026-08-29T08:30:03.723024+00:00, sha 0494ff1dfca2)
  - site_page: https://puma.io/puma5 (fetched 2026-08-29T08:30:03.726805+00:00, sha 7dffeb67410a)
- Data as of 2026-08-30T08:39:29.467469+00:00.