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Build lightning fast web apps with fewer bugs

Lucky is a web framework written in Crystal. It helps you work quickly, catch bugs at compile time, and deliver blazing fast responses.

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🚀 Say goodbye to slow

Lucky is extremely fast and uses very little memory. You and your users will love the extra dose of speed.

🔋 Batteries included

Authentication, asset management, CORS, database ORM, and more can all be included when creating a new Lucky project.

😁 Fewer bugs. More joy

Instead of finding bugs in QA or in production, Lucky is designed to catch as many bugs as possible at compile time.

# Why is modern web development so complicated?

Have you ever thought:

  • “Why do I have to write so much boilerplate?”
  • “How do so many bugs make it to production?”
  • “Why is my app so slow!?”
  • “Why do I have to choose between fast prototyping and long term maintainability?”

# What if you could create something quickly and maintain it for years to come?

  • Generators for quick code creation
  • Built in authentication (Optional)
  • Secure by default
  • Built in Webpack config to get an SPA off the ground fast (Optional)
  • Insanely fast execution so users aren’t left waiting
  • Powerful type system that helps catch bugs before they ever hit production

If this sounds interesting, let’s get started.

# What does Lucky look like?

Lucky uses Action classes for handling HTTP request and responses. The classes map the routes and parameters it handles to a response block. Lucky can generate these classes for you with ’lucky gen.action`.

Using a class per action provides very solid automatic error detection, as well as generation of routing, path, and link helpers and methods.

# JSON API 

class Api::Users::Show < ApiAction get "/api/users/:user_id" do json user_json end private def user_json user = UserQuery.find(user_id) {name: user.name, email: user.email} end end

# Database 

# Set up the model class User < BaseModel table do column last_active_at : Time column last_name : String end end # Add some methods to help query the database class UserQuery < User::BaseQuery def recently_active last_active_at.gt(1.week.ago) end def sorted_by_last_name last_name.lower.desc_order end end # Query the database UserQuery.new.recently_active.sorted_by_last_name

# Rendering HTML 

class Users::Index < BrowserAction get "/users" do users = UserQuery.new.sorted_by_last_name html IndexPage, users: users end end class Users::IndexPage < MainLayout needs users : UserQuery def content ul class: "users-list" do users.each do |user| li { link user.name, to: Users::Show.with(user) } end end end end

# JavaScript Components 

class Home::IndexPage < MainLayout def content # Lucky includes Webpack! # You can enable React or Vue.js support. Then... # Mount your JavaScript component/app tag("MyApp", title: "MyApp is the best") # Optionally render regular HTML for non-interactive elements footer "Copyright MyApp 2025" end end

# Not quite ready to try Lucky?

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