Convert Zip To Sb3

Converting a ZIP of a Scratch Project into an .sb3 File

Many Scratch projects are shared as .sb3 files (the official Scratch 3 project format), but sometimes you’ll receive a Scratch project packaged as a ZIP archive containing a project.json and associated assets (images, sounds, etc.). Converting that ZIP into a valid .sb3 file is straightforward because an .sb3 is simply a ZIP archive with a specific internal structure and a .sb3 file extension. Below is a concise, practical guide you can use as a draft article or how‑to.

✅ Do:

• Keep backups of original ZIPs until you’ve tested the SB3.
• Use local conversion methods for sensitive projects.
• Verify the SB3 opens in the Scratch offline editor or at scratch.mit.edu.

Method 2: Extract and Re-ZIP (For Folders)

If you have a folder that contains a Scratch project structure (e.g., you modified an extracted SB3): convert zip to sb3

1. Open the folder and ensure it contains project.json.
2. Select all contents inside the folder (not the folder itself).
3. Compress them into a ZIP archive:
   • Windows: Right-click → Send to → Compressed (zipped) folder.
   • macOS: Right-click → Compress X items.
   • Linux: Use zip -r project.zip . from inside the folder.
4. Rename the resulting .zip file to .sb3.

Batch process

for file in os.listdir('.'): if file.endswith('.zip'): zip_to_sb3(file) Converting a ZIP of a Scratch Project into an

Save as convert.py and run in the folder with your ZIPs. Keep backups of original ZIPs until you’ve tested the SB3

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Command-line example (Linux/macOS)

Assuming files are in folder scratch_project/ with project.json and assets/:

cd scratch_project
zip -r ../project.sb3 . 

Then open or rename as needed (the .zip produced is already correct; give it .sb3 extension if desired).