CRails — Clean Rails - The most beautiful compiled web framework

Current status: a port of Ruby on Rails. At this point CRails is simply a port of Ruby on Rails to Crystal. We are porting the framework in its current form: the framework itself, its spirit and the beauty of its code. The code is being ported from Rails one-to-one, so that refactoring can happen later — this is a draft, not even a first release.

Philosophy

The project's philosophy — explicit contracts first, lessons from Rails and Ruby, why Crystal and not Rust, and the promises the framework intends to keep — lives in IDEA.md. It is effectively a roadmap and a promise for the future, not a description of what is already implemented.

The best performance in class

Median RPS, official once-campfire-verification harness, AMD Ryzen 9 3900X stand:

Beats Rust in some cases, but with beautiful code and the MVC pattern — see more at the original repository.

Ecosystem

CRails is assembled from standalone shards, each living in its own repo under github.com/OrelSokolov:

Base (resolved by the root shard.yml):

• active_support.cr — core utilities, Concern, inflections
• attr_reader.cr — Ruby-style attr_reader macros
• erb.cr — ERB templating (ECR)
• action_view.cr — views, helpers, FormBuilder
• action_pack.cr — controllers, routing, middleware
• importmap.cr — importmap-based JS assets
• propshaft.cr — asset pipeline (+ brotli.cr precompression)
• active_record.cr — ORM, migrations, adapters (db/pg/sqlite3)
• railties.cr — the crails CLI, generators, app glue (lives in this repo at railties.cr/)
• icr.cr — crails console
• project_watch.cr — crails watch

Optional layers (add to your app's shard.yml when needed):

• active_job.cr — background jobs
• action_cable.cr — WebSockets
• action_mailer.cr — email
• action_mailbox.cr — inbound email
• active_storage.cr — file uploads
• action_text.cr — rich text
• action_bot.cr — bots (webhooks + SSE)
• devise.cr — authentication
• turbo.cr — Hotwire Turbo
• live_view.cr — LiveView-style reactive views
• kiq.cr — Sidekiq-compatible jobs backend
• active_backup.cr — database backups
• action_mcp.cr + active_agent.cr — MCP servers and AI agents
• serverx.cr — nginx-model zero-alloc HTTP server (buffer per connection, offset parser, master/workers via SO_REUSEPORT), compatible with any HTTP::Handler

License

MIT

What this is

A full clone of the Ruby on Rails API on Crystal, as 1:1 as possible in the end interface — so that a developer moving from Ruby/Rails feels no difference. Goal: Rails application code ports to Crystal nearly verbatim.

The only namespace difference: CRails instead of Rails.

• CRails.application, CRails.env, CRails.root, CRails.logger — as Rails.* was in Rails.
• ERB → ECR (the only visible substitution — the language is different).
• Commands: crails instead of rails (crails new, crails server, crails generate, crails console, crails routes, crails db:migrate).