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We believe in more than frameworks, we believe that minimalist and well crafted software will change the world. Lets build your ideas with elegance and simplicity with Fractal.


We use better tools, we move fast, we love innovation ... Oh and Fractal is fractal, this means you can embed any Fractal app inside another with no effort.


  • Minimal, simple and composable architecture that scales
  • Simple inter-component comunication via messages, you can broadcast messages to all components and listen for them
  • Async operations made simple. Fractal make a wide use of async functions and you can use it in your app
  • We gives you powerful patterns and composing tools that helps you to build small and large apps like Legos
  • Excellent developer experience. We love to improve your experience, for now we have hot-swapping support but wait more dev tools in the short term
  • Lazy loading support
  • Prerendering and Server Side Rendering support
  • Blazingly fast because we use caching. This is possible because actions are the unique way of updating the state and the component view changes only depends on state so we only compute components that are actually needed. For DOM updates we use Snabbdom that it's pretty fast but you can use whatever DOM library you want, e.g. React
  • Excellent error / warn handling:
    • Your app will never crash for a runtime error (Actually under testing, if you have an uncovered case please open an issue)
    • Application logs are meaningful. No more WTF?!! errors, if you see one, report it and we will fix it in a timely manner
  • You can easly serialize side effects, this means you can run Fractal in a Web Worker, in a server via Websockets or even in a remote browser via WebRTC, crazy right? :'). An example comming soon...
  • High code quality, we love that!! We helps you to achive it in your proyect ❤️

See the design document. In order to be scalable, Fractal is implemented using Typescript

We make use of Fractal in our projects and this library is continuosly evolving, be in touch...

How it works?


  • Module: A engine for you app, connect a component tree to the external world.
  • Component: Is a part of your app, a component have:
    • State: The component changing data.
    • Inputs: Async processes that recieve messages (data) from other components or outside the app, in an Input you can:
      • Send messages to other Inputs (same Component).
      • Send messages to other Components via Inputs.
      • Send messages outside the aplication with Tasks.
      • Perform side effects but only while prototyping, after that you should use Tasks.
    • Actions: The only way to change the state.
    • Interfaces: Here lives continous and hierachical connections with external world, the most common Interface is the view.
    • Groups: Data that can be used when a component is initialized, we use it for styles.
  • Task: A mechanism to send messages to external world in a clean way (AKA perform side effects nicely), e.g. get some data from your local database.
  • Handlers: Perform side effects, they receive messages from Tasks and hierachical structures from Interfaces and handle them.


  • Fractal architecture: This is a kind of unidirectional user interface architecture see an insightful article here by @staltz.
  • Reactive views: We use Snabbdom for rendering.
  • CSS in JS: We create styles in JS using TypeStyle, see this Vjeux slides.
  • Typescript: We use TypeScript that is the same as JS but optionally you can have some types, we use it for better tooling see this Eric Elliot article. Our lemma is to be fast with dynamic types but use types for stable code and some data modeling. We use it for:
    • A nice autocomplete for Styles and JavaScript
    • Errors in Styles (via TypeStyle)
    • Type some data models
    • Type functions
    • Catch syntax errors and a few bugs
  • Hot-swapping: Live develop your application with no state loss. It gives you a nice developer experience.
  • JS Bundling / Loading: FuseBox 🔥🔥🔥 We love it! is fast, clear and powerful ... Oh! I said it's fast? .. Well, it's blazingly fast, let's try it!


  • Nice in-app debugger with timetravel debugging and a component tree view
  • A list of all possible errors can happen with their respective solution, this can evolve including links within error logs
  • We have high code quality standards and development flows you and your team can follow, from prototyping to production code (We will publish these soon ...)
  • Prototype with ease and transform to a production level code with easy (Guide comming soon...)
  • We support hot-swapping code in production 🌹 (soon)

Getting started

The recomended way is using FuseBox, please download the Fractal-quickstart or Fractal-featured repo depending on your needs, this gives you all things ready to start hacking.

Or in nodejs, browserify, Webpack like environments:

npm i --save fractal-core

Or with yarn:

yarn add fractal-core

Note for VSCoders, you can use the Fractal VSCode Extension


Working examples you can start hacking immediately:


See our tutorial and the examples (We are refactoring examples and tutorial, be in touch ...).

Note: The tutorial is not updated, we will update it soon.

Related Projects

Development Notes

See our Development Documentation


npm i fractal-core

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  • carloslfu