: This usually happens if your ZIP file contains a folder. Scratch requires the project.json to be at the "top level" of the archive.
If you’ve ever tried to open a Scratch project file ( .sb3 ) in a standard text editor, you were likely greeted by a chaotic wall of random characters. It looks like binary gibberish.
Note that this method requires you to have Scratch installed on your computer, as well as the scratch command-line tool.
| Feature | SB3 File | ZIP File | | :--- | :--- | :--- | | | Scratch 3.0 project file | General-purpose archive for compressing and storing any file(s) | | File Structure | A ZIP archive containing project.json and assets | A ZIP archive containing any files and folders | | Key Requirement | Must contain a valid project.json at the archive root | No specific internal structure required | | Extension | .sb3 | .zip | | Renaming | Can be renamed to .zip and opened with any archive tool | Can be renamed to .sb3 , but will only be valid if it contains a proper Scratch project structure | convert zip to sb3
Inside an .sb3 file (which is really a renamed ZIP), you'll typically find:
Select Compress to ZIP file (or Send to > Compressed (zipped) folder on older Windows versions). Mac: Select Compress [Number] Items . A new .zip archive will be generated in that directory.
inside the folder – not the folder itself . Use Ctrl+A (Windows/Linux) or Cmd+A (Mac). : This usually happens if your ZIP file contains a folder
user wants a long article on converting ZIP files to SB3. The plan covers understanding the topic, conversion methods, troubleshooting, and a concluding guide. I need to search for a variety of resources including tutorials, tools, and official information. I'll start by searching for the main keywords and then open some promising pages. search results include several relevant resources. I'll open the Scratch Wiki page on the file format, the ezyzip online converter, the 101convert guide, the compresszip tool, and the SB3 file format documentation to gather detailed information. opened pages provide detailed information on the SB3 format, online conversion tools, manual methods, and troubleshooting. The search results also include other relevant pages like the Scratch Wiki on porting projects and file format differences. I'll open those as well to gather more comprehensive information for the article. search results provide a good foundation. The article will cover the relationship between ZIP and SB3, various conversion methods (online tools, manual, batch processing), solutions to common problems, and advanced use cases like converting SB2 files and extracting project assets. I will structure the article with an introduction, sections on the ZIP-SB3 relationship, conversion methods, troubleshooting, advanced uses, FAQs, and a conclusion. a Scratcher, you've likely encountered the common .sb3 file format—the standard for projects created in Scratch 3.0. But you might also have run into a .zip file that contains Scratch project data, leaving you wondering how to open it properly. This guide will walk you through everything you need to know about converting ZIP to SB3, from manual methods to online tools, troubleshooting common issues, and even a few advanced tricks for power users.
✅ Correct: The ZIP’s root contains project.json , not a subfolder.
If you're comfortable with using command-line tools, you can use tools like unzip and scratch to convert ZIP to SB3. It looks like binary gibberish
| From | To | Method | |------------|-------|-------------------------------| | .zip | .sb3 | Rename file extension | | Unzipped folder | .sb3 | Zip contents → rename to .sb3 |
Scratch 3.0 files are essentially . Think of them like a suitcase. When you save a project, Scratch packs all your assets (costumes, backdrops, sound files) and a master instruction sheet (a JSON file called project.json ) into a suitcase.
There are several scenarios where a developer or student might need to pack a ZIP file back into an SB3 file: