Puma

Spec sheet

Product

Puma is a fast, concurrent HTTP 1.1 server designed for Ruby/Rack applications.Read 7 Oct 2026 · puma.io

Deployment

The deployment guide says Puma can be used as a development server, though most users run it in production deployments.Read 7 Oct 2026 · puma.io

Integrations

The documentation lists community plugins for exporting metrics to Prometheus and sending metrics to StatsD.Read 7 Oct 2026 · puma.io

License

Puma is licensed under the BSD 3-Clause license.Read 7 Oct 2026 · puma.io

Founded

2011Read 28 Sep 2026 · puma.io

Concurrency

Puma serves requests in separate threads and can use pre-forked worker processes in cluster mode.Read 7 Oct 2026 · puma.io

Frameworks

Puma is the default server for Ruby on Rails and can also run Sinatra applications.Read 7 Oct 2026 · puma.io

Monitoring

Puma includes a built-in status and control app, and its docs describe using process monitors such as systemd or rc.d.Read 7 Oct 2026 · puma.io

Ruby implementations

Puma works with MRI Ruby and JRuby, and the documentation also names TruffleRuby as a truly parallel Ruby implementation.Read 7 Oct 2026 · puma.io

Security support

The security policy supports the latest release in the 8.x and 7.x series and marks all other releases unsupported.Read 7 Oct 2026 · github.com

SSL requirement

Puma supports SSL sockets when OpenSSL development files are installed; without them, it installs but does not allow SSL connections.Read 7 Oct 2026 · puma.io

Standalone

Puma supports SSL, zero-downtime rolling restarts, and a built-in request bufferer, allowing deployment without a reverse proxy.Read 7 Oct 2026 · puma.io

Vulnerability reporting

The security policy directs vulnerability reports to GitHub or Evan Phoenix.Read 7 Oct 2026 · github.com

Windows limitation

Cluster mode is not supported on Windows because it lacks fork(2).Read 7 Oct 2026 · puma.io

Plans and prices

Every Puma plan and price →

Where Specifiction places it

• Web Server Software#22 of 367.5