What you get for a .DEM file
We don't have a dedicated viewer for this format, so we identify and inspect it instead — honestly, only what can be read from the file.
Drop your .DEM file
Choose it or drag it in. It's read right here in your browser.
We identify it
We read the magic bytes to tell what the file really is, its MIME type, and whether the name matches the contents.
See the details
Any metadata we can extract (dimensions, EXIF/GPS, document author and dates), a hex view, plus readable text and strings found inside.
What is a .DEM file?
Plain text that programs, servers and people write every day.
A .DEM file is a data file used to store video game demonstrations. It typically contains recorded gameplay footage from titles such as Half-Life, Counter-Strike, and Quake. These files are opened and played back using the original game engines developed by Valve and other creators.
Programs that open .DEM files
| Full name | Recorded Game Demo File |
|---|---|
| Developer | Valve (GoldSrc / Source engine; format also used by id Software and others) |
| First released | 1996-1998 (Quake/GoldSrc era); Valve Source DEM since 2004 |
| Category | Text & Code |
| MIME type | application/octet-stream |
| Signature | 48 4C 32 44 45 4D 4F 00 "HL2DEMO\0" - Valve Source engine demo header |
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Frequently asked questions
Is my .DEM 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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