What Is Blockly: Visual Block-Based Coding from Google

Blockly is an open-source library (a reusable piece of code) from Google for building visual, block-based coding editors, where you build a program by dragging and snapping blocks together like puzzle pieces instead of typing lines of code. Blockly is not an app a child uses directly — it is the "engine" behind many popular tools for learning to code.

Table of Contents

• How Blockly Works
• Blockly vs Scratch
• Why It Matters for Kids

How Blockly Works

Each Blockly block represents one command — for example "repeat 10 times" or "if ... then". Blocks only connect when their shapes match, so children can hardly make typing (syntax) mistakes like a forgotten semicolon. As the blocks are assembled, Blockly automatically translates them into text code such as JavaScript or Python in the background. This is a lot like Scratch: both use colorful blocks you drag around. The difference is that Scratch is a finished product for making animations and games, while Blockly is a component developers use to build their own coding editors. For example, a child who stacks the blocks "repeat 4 times → move forward → turn right" to move a robot on screen is really producing the same loop code a programmer would write in Python. Google released Blockly in 2012, and today the technology powers well-known platforms like Code.org and MakeCode used by tens of millions of children worldwide. Because many of these tools are free and web-based, a child can start experimenting with Blockly right in the browser without installing anything.

Blockly vs Scratch

The main difference: Scratch is a finished app for making games and animations, while Blockly is the building material developers use to create their own coding editors. Both use colorful drag-and-drop blocks, so to a beginner they feel similar. Scratch was made by MIT and runs directly at scratch.mit.edu, while Blockly usually appears inside other platforms such as Code.org or MakeCode. For a child just starting out, the learning experience is nearly the same: snapping blocks together to move a character or a robot. A child can try that first block in a free Algonova coding class.

Why It Matters for Kids

Blockly makes the first step of learning to code child-friendly: kids can focus on logic and sequence instead of tricky typing rules. In the Algonova coding course, children start with block coding and gradually move up to text — just like stepping from blocks to a real programming language. Understanding how blocks work also helps kids grasp ideas like loops and conditions faster when they switch to text coding.

Want your child to try? Join a free coding class and watch them snap their very first block together.