Scratch Specification

A detailed explanation of how Scratch 3.0 works. WIP. This is in early stages and not yet complete.

Introduction

An explanation of what this spec is trying to achieve.

Formal definitions for basic Scratch concepts.

How scripts run.

Every. Block. Ever.

The file formats used to save and load Scratch runtime objects.

How Scratch receives inputs, renders images, and plays sounds.

How Scratch handles requests to external servers, as well as cloud variable manipulation.

How Scratch interacts with programmable hardware components.