How to open a code or text file online
Three steps, a few seconds, no software.
Open your .SB3 file
Drop it on the box, choose it from your device, or paste the text straight in.
View it instantly
Your .SB3 file opens neatly formatted with line numbers.
Search, copy or download
Search the text, jump to any line, then copy what you need or download a clean copy.
What is a .SB3 file?
Plain text that programs, servers and people write every day.
An SB3 file is a Scratch 3.0 project, a visual programming project made with MIT's Scratch. Open it at scratch.mit.edu (File > Load from your computer) or in the free Scratch Desktop app. The file is a standard ZIP archive; rename it to .zip to inspect the JSON code and media assets inside.
Programs that open .SB3 files
| Full name | Scratch 3.0 Project File |
|---|---|
| Developer | MIT Media Lab (Scratch Foundation) |
| First released | January 2, 2019 (Scratch 3.0 public launch) |
| Category | Text & Code |
| MIME type | application/x.scratch.sb3 |
| Signature | 50 4B 03 04 "PK" - ZIP local file header |
Related viewers
Every viewer is free to use.
Frequently asked questions
Is my .SB3 file uploaded anywhere?
No. The file is read and highlighted for you.
Why do some characters look wrong (é, ł)?
That usually means the file was saved in one encoding and opened in another. We detect UTF-8, UTF-16 and the Windows-1250/1252 code pages automatically and show which one was used.
Can it handle huge log files?
Yes, up to 50 MB. Only the lines on screen are drawn, so scrolling stays smooth. Syntax colours are switched off for files over 1.5 MB to keep things fast.
How do the log level filters work?
We find levels like ERROR, WARN, INFO and DEBUG on each line. Lines without a level, such as stack traces, stay with the entry above them, so filtering to errors keeps the full trace.
Can I edit the file?
This is a viewer. To change code, download it or copy it into your editor. Converting encodings and line endings is planned.
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