Blockly is a visual programming editor by Google that uses drag-and-drop blocks. It’s the engine that powers the most popular coding education programs world wide.

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The Blockly library adds a customizable editor to your app that presents coding concepts as interlocking blocks. It produces clean code in your desired language and allows for custom blocks tailored to your application.

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Blockly is the foundation for some of the largest block-based coding products, such as Scratch and Code.org, which serve tens of millions of students each year.

Blockly is 100% client side, with no server side dependencies, and compatible with all major browsers: Chrome, Firefox, Safari, Opera, and Edge.

Why Blockly

Blockly is the preferred choice for platforms aiming to deliver versatile and intuitive programming experiences

The Blockly library offers a comprehensive suite of APIs and tools, empowering coding platforms to provide a customizable environment for their unique requirements.

The Blockly editor uses interlocking, graphical blocks to represent code concepts like variables, logical expressions, loops, and more. It allows users to apply programming principles without worrying about syntax.

A platform-agnostic library, Blockly is preferred by coding platforms seeking consistency, flexibility and convenience. Blockly is compatible with all major browsers and works on both web and mobile.

Create unique tools, applications, and platforms that meet your specific program requirements.

Blockly for developers

Developer Resources

Add functionality to Blockly with Plugins. Add fields, define themes, create renderers, and much more.

Explore plugins

Blockly codelabs provide step-by-step instructions on how to use and customize Blockly.

Explore codelabs

Sample projects show how to use many of Blockly's features.

Explore samples

The Blockly Developer Forum is the place to ask and answer questions.

Go to forum

Block-based coding is for all programmers, of any field or level. Explore the latest from Blockly and connect with other developers at our Blockly Summits.

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Blockly provides a really good entry point into computer science, without worrying about things like a missing semicolon, or a for loop that doesn’t have all of the right pieces.

Jessica Kulwik, Software Engineering Manager, Code.org

Mark Friedman, Co-founder, App Inventor

Proven and reliable

100+

partners

10+

years

94+

translations

Trusted by developers

Blockly is the engine behind some of the largest and most loved block-based coding products.

  • Code a hero with Scratch for CS First

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  • Build your own Star Wars game with Blockly and Code.org

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  • Imagine a world and make it come to life with Scratch

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FAQ

How can I get started with Blockly?

If you are a software developer who wants to get started with Blockly, you should begin by reading our Get Started Docs and then try our Get Started Codelab.

If you are a teacher or student interested in block-based coding, you should check out a lesson through an educational product built on Blockly, such as CS First, Code.org, or Scratch.

Who is Blockly for?

The Blockly library is for software developers that want to add an editor to their app that represents coding concepts as interlocking blocks. From a developer's perspective, Blockly is a ready-made UI for creating a block-based language.

If you are not a developer, you most likely will want to engage with Blockly through a product that is built on Blockly, like Scratch or App Inventor. Check out the Blockly partnerships section for examples of other applications that are built on Blockly.

What are some of the benefits of block-based coding?

Block-based coding allows users to apply programming principles without having to worry about syntax or the intimidation of a blinking cursor on the command line, making the learning curve for aspiring programmers easier. By reducing the need to learn syntax, block-based coding allows users to focus entirely on the logic behind conditionals, loops, variables and other core concepts without worrying about unbalanced parenthesis or missing semicolons.