What is an SB3 file?
An .SB3 file is a Scratch 3.0 Project. MIT and the Scratch Foundation developed this format for the Scratch visual programming language. The file stores all the code, sprites, sounds, and background images used in a Scratch program. Underneath, an .SB3 file is a standard ZIP archive. It contains a `project.json` file for the code structure and various media files like .SVG, .PNG, and .WAV.
How to open SB3 files?
You can open these files using the official Scratch online editor by clicking 'File' and then 'Load from your computer'. Alternatively, you can use the offline Scratch Desktop application. If you want to see the media assets inside the file, you can rename the .SB3 extension to .ZIP and open it with archive tools like 7-Zip or your system's default archive utility.
viewer.online/sb3 analyzes .SB3 files to identify their exact format and creator software, shows which programs can open the file, and usually previews it directly in your browser.
Best practices and troubleshooting
If your .SB3 file does not load in Scratch, the file might be corrupt. You can test the file integrity by opening it as a ZIP archive. Ensure you do not modify the `project.json` file manually unless you know the exact JSON structure, as this will break the project. Because .SB3 files can sometimes have multiple possible meanings or variations, we recommend using viewer.online/sb3 to identify the actual format of your file.
Software and tools
- Scratch 3.0: The primary online editor for creating and viewing these projects.
- Scratch Desktop: The offline version for Windows and macOS.
- 7-Zip: A free tool to inspect the compressed contents of the archive.
Summary
Because .SB3 files use the known ZIP format, viewer.online/sb3 can safely open and display them online, eliminating compatibility problems. You can instantly inspect the project structure and media files without installing any extra software.