puma/puma

Health v2 · maintenance only

Adoption not part of the score

7914 stars · 1489 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

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

library · maturity stable

http-server web-framework concurrency cli web-development backend developer-tools ruby windows cross-platform rack ruby-on-rails sinatra thread-pool cluster-mode ssl zero-downtime-restarts http1-1 linux macos

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markdown · JSON · MCP: product_card(name="puma/puma")