Lightning Fast, Super Simple web framework. Inspired by Sinatra kemal web-framework websocket api fast simple efficient json rest
0.7.0 released
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# Kemal [![Build Status](](

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Lightning Fast, Super Simple web framework for Crystal. Inspired by Sinatra but with superior performance and built-in WebSocket support.

Kemal is under heavy development and currently supports Crystal latest.

Super Simple <3

require "kemal"

# Matches GET "http://host:port/"
get "/" do
  "Hello World!"

# Creates a WebSocket handler.
# Matches "ws://host:port/socket"
ws "/socket" do |socket|
  socket.send "Hello from Kemal!"

Build and run!

crystal run src/

Go to http://localhost:3000

Check documentation or samples for more.

Super Fast <3

Numbers speak louder than words.

| Framework | Request Per Second | Avg. Response Time | | :------------ |:---------------:| -----:| | Kemal (Production) | 64986 | 170μs | | Sinatra (Thin) | 2274 | 43.82ms |

These results were achieved with wrk on a Macbook Pro Late 2013. (2Ghz i7 8GB Ram OS X Yosemite)


  • Support all REST verbs
  • Websocket support
  • Request/Response context, easy parameter handling
  • Middlewares
  • Built-in JSON support
  • Built-in static file serving
  • Built-in view templating via ecr


You can read the documentation at the official site


Thanks to Manas for their awesome work on Frank.

  github: kemalcr/kemal
  version: ~> 0.7.0
Crystal none

Dependencies 0

Development Dependencies 0

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