Raptor

Raptor is a high-performance, preloading, multi-process, multi-threaded Ruby 4+ web server implementing Rack 3.2+, leveraging Ractors for parallel HTTP/1.1 and HTTP/2 request processing, native C extensions for HTTP parsing and HPACK compression, and NIO for non-blocking I/O.

Installation

Install the gem and add to the application's Gemfile by executing:

bundle add raptor

If bundler is not being used to manage dependencies, install the gem by executing:

gem install raptor

Usage

# hello_world.ru

# frozen_string_literal: true

run proc { |_env| [200, { "content-type" => "text/plain" }, ["Hello, World!"]] }

> bundle exec raptor -w 4 -t 3 hello_world.ru
[Raptor 91348|main|main] Cluster initializing:
[Raptor 91348|main|main] ├─ Version: 0.5.0
[Raptor 91348|main|main] ├─ Ruby Version: ruby 4.0.5 (2026-05-20 revision 64336ffd0e) +YJIT +PRISM [arm64-darwin23]
[Raptor 91348|main|main] ├─ Master PID: 91348
[Raptor 91348|main|main] │  └─ 4 worker processes
[Raptor 91348|main|main] │     ├─ 1 server thread
[Raptor 91348|main|main] │     ├─ 1 reactor thread
[Raptor 91348|main|main] │     ├─ 1 pipeline ractor
[Raptor 91348|main|main] │     ├─ 1 pipeline collector thread
[Raptor 91348|main|main] │     ├─ 3 worker threads
[Raptor 91348|main|main] │     └─ 1 stats thread
[Raptor 91348|main|main] └─ Listening on 0.0.0.0:9292
[Raptor 91350|main|main] Worker 0 booted
[Raptor 91351|main|main] Worker 1 booted
[Raptor 91352|main|main] Worker 2 booted
[Raptor 91353|main|main] Worker 3 booted

> curl localhost:9292
Hello, World!%   

Also works with rackup and rails server:

> bundle exec rackup -s raptor hello_world.ru
> bundle exec rails server -u raptor

(Micro) Benchmarks

Raptor 0.5.0 vs Puma 8.0.2:

Protocol	Raptor	Puma
HTTP/1.1	20.1k req/s	20k req/s
HTTP/1.1 (keep-alive)	61.4k req/s	39.1k req/s
HTTP/2	22.8k req/s	N/A

ruby 4.0.5 (2026-05-20 revision 64336ffd0e) +YJIT +PRISM [arm64-darwin23] 4 workers, 3 threads, 12 concurrent connections

See bin/benchmark for more details.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run bundle exec rake to compile native extensions and run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/joshuay03/raptor. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Raptor project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.