Serviette

A minimal, Ractor-safe web framework for Ruby 4.0.

Inspired by Sinatra, Serviette provides a simple DSL for declaring route handlers.

require 'serviette'

class MyApp < Serviette::Application
  get '/' do
    redirect '/hello/world'
  end

  get '/hello/:name' do |name|
    "Hello, #{name}!"
  end

  get '/users/:id' do
    content_type 'application/json'
    { id: params["id"] }.to_json
  end
end

# config.ru
run MyApp

Route handlers can return a string (automatically wrapped as a 200 response), an integer status, or a Rack [status, headers, body] tuple with either the headers or the body left out. Helpers like status, headers, content_type, redirect, and not_found are available.

To customize 404s, register a handler with not_found { |message| ... }. It renders unmatched paths and not_found(message) calls, and can use erb:

not_found { |message| erb :not_found, props: { message: message } }

ERB templates are precompiled at boot and made Ractor-shareable. A layout.erb is automatically used if present (override with layout: or disable with layout: false).

class MyApp < Serviette::Application
  self.views = File.join(__dir__, "views")

  get '/' do
    @title = "Home"
    erb :index
  end
end