Cappuccino is an open-source framework that lets you build powerful, desktop-class applications that run in a web browser. Instead of wrestling with HTML, CSS, and the DOM, you can build your app using Objective-J, a superset of JavaScript modeled on Objective-C.

Cappuccino faithfully implements the proven design patterns of NeXTSTEP/Apple's Cocoa frameworks, allowing you to build incredibly complex and reliable applications with a fraction of the code.

✨ Project Status: Active Development & Node.js Transition Cappuccino has been under continuous development since 2008 and is actively maintained. We have recently finalized a major transition to a modern, Node.js-based toolchain. The current release is a production-ready Release Candidate, with a formal release scheduled for 2025. It's stable, fast, and ready for your next project.

Why Use Cappuccino?

Cappuccino is not for building simple websites. It's for building applications—especially complex, data-rich, line-of-business tools where productivity and user experience are paramount.

💻 True Desktop Behavior, Out-of-the-Box: Applications built with Cappuccino behave like native desktop software by default. This includes a rich palette of UI controls, full keyboard navigation and focus management, and multi-level undo/redo support — all without writing a single extra line of code. See the Kitchen Sink demo.
🚀 Incredible Productivity: Write less code. High-level abstractions and a powerful object-oriented model mean you focus on your app's logic, not the browser's quirks.
🏛️ Stable & Mature: Built on decades of proven API design from Cocoa®, Cappuccino provides a stable foundation, free from the churn common in the JavaScript ecosystem.
🧱 True Object-Oriented Architecture: Objective-J's message-passing architecture promotes loose coupling and clean design, making large-scale applications easier to build and maintain.
🌐 Platform Independent: Develop on macOS, Windows, or Linux. Deploy to any modern web browser.

🚀 Quick Start

Get a new Cappuccino application running in five minutes.

1. Prerequisites

You'll need Node.js (LTS versions are recommended) and npm.

2. Configure npm (Recommended First-Time Setup)

To avoid potential permission issues with global packages, it's best to set a local directory for npm.

# Tell npm where to install global packages
npm set prefix ~/.npm

# Add this directory to your path in .zshrc, .bash_profile, etc.
export PATH="~/.npm/bin:$PATH"

Restart your shell or source your profile (source ~/.zshrc) for the changes to take effect. For more details, see the npm documentation.

3. Install Cappuccino

npm install -g @objj/cappuccino

4. Create and Run Your First App

# 1. Generate a new project
capp gen HelloWorld

# 2. Move into the new directory
cd HelloWorld

# 3. Start a local web server (Python 3 example)
python3 -m http.server 8000

# 4. Open your new app in any modern browser!
# http://localhost:8000

That's it! You now have a fully-functional Cappuccino application.

What is Objective-J?

Objective-J is a strict superset of JavaScript, which means all JavaScript code is valid Objective-J code. It adds the powerful object-oriented features of Smalltalk and Objective-C, like explicit message-passing and class-based inheritance.

The syntax might look different, but it's designed for clarity and power.

Objective-C:

NSString *greeting = [NSString stringWithFormat:@"Hello, %@!", name];

Objective-J:

var greeting = [CPString stringWithFormat:@"Hello, %@!", name];

You can mix and match pure JavaScript and Objective-J, even in the same file. Your Objective-J code is transpiled into highly-optimized JavaScript for deployment, but can also be run directly in the browser during development.

Find Out More

Official Website: cappuccino.dev
Documentation & Tutorials: cappuccino.dev/learn/
Gitter Community Chat: gitter.im/cappuccino/cappuccino
GitHub Wiki: github.com/cappuccino/cappuccino/wiki
FAQ: cappuccino.dev/support/faq.html
Report a Bug: Create a GitHub Issue

Frequently Asked Questions (FAQ)

Q: Can I use Cappuccino on Windows/Linux?
A: Yes. The development tools run on Node.js and are platform-independent. Applications can be developed on any OS and deployed on any web server.

Q: Do I have to use Xcode?
A: No. You can use any code editor. Xcode offers optional visual development tools for macOS users, but it is not required.

Q: Hasn't Apple moved on from Objective-C, making these APIs obsolete?
A: While Swift is Apple's newer language, Objective-C and AppKit remain foundational, actively supported technologies used in many of Apple's flagship applications. Cappuccino leverages the stability and power of this time-tested API design, which is independent of Apple's future product roadmap.

Q: How do I integrate my own HTML, CSS, or JavaScript libraries?
A: Cappuccino abstracts away the DOM, but you can still integrate other web technologies. The CPWebView control allows you to embed arbitrary HTML/CSS/JS content. Since Objective-J is a superset of JavaScript, you can use JS libraries and call JS functions directly from your Objective-J code.

Q: What are the advantages over React or Vue?
A: React and Vue are excellent libraries for building web UIs. Cappuccino is a comprehensive framework for building entire applications. It provides a fully integrated stack—including a mature UI library, event handling, and data management—designed for large-scale development.

Beyond this, Cappuccino provides a more integrated and powerful data-binding layer inspired directly by Cocoa, which dramatically reduces boilerplate code for complex UIs:

Sophisticated Data Bindings: Go beyond simple state-to-view mapping. Cappuccino's binding technology, based on Key-Value Coding (KVC), allows you to declaratively link your data models directly to your UI components.
Powerful Controller Layer: Use dedicated controller objects (like CPArrayController) to mediate between your data and your views. These controllers automatically handle sorting, filtering, and selection state, completely decoupling your UI from your business logic.
Advanced Filtering with Predicates: You can filter a table of thousands of items simply by setting a predicate (a declarative filter rule, e.g., lastName BEGINSWITH 'S') on its controller. The UI updates instantly. This eliminates tons of manual state management and filtering logic code.
Automatic Value Transformation: Easily format data for display (e.g., dates, currency, booleans to "Yes/No") directly within the binding itself using value transformers, keeping your model data pure and your view logic minimal.

Q: Does the LGPL license permit closed-source commercial applications?
A: Yes. The LGPLv2 license allows you to build and distribute proprietary, closed-source applications using Cappuccino. You are only required to share the source code of any modifications you make to the Cappuccino framework itself. Your own application code remains your own.

Building from Source

If you want to contribute to Cappuccino or use the absolute latest, un-released changes, you can build it from source.

git clone https://github.com/cappuccino/cappuccino.git
cd cappuccino
npm install (This bootstraps the build process using the latest release)
jake build
jake dist (This will install the locally-built toolchain, potentially overwriting your npm version)

To switch back to the official release, simply run npm install -g @objj/cappuccino again.

License

Cappuccino is released under the GNU Lesser General Public License (LGPL) version 2.1.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

Cocoa® is a registered trademark of Apple Inc.