Scratch is a programming language that makes it easy to create your own interactive stories, animations, games, music, and art -- and share your creations on the web. As young people create and share Scratch projects, they learn important mathematical and computational ideas, while also learning to think creatively, reason systematically, and work collaboratively.
- Scratch is a block-based programming environment. Blockly is a library for MAKING block-based programming environments. Therefore, they serve different purposes.
- It's not related. Scratch is a programming language and Blockly is an API basically.