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View a UST file online, free

Open and read .UST files online. View source, logs and text with syntax highlighting, search and line numbers, free.

Drop your .UST file here

Opens your .UST file right here.

Choose file
Up to 50 MB · 160+ text and code extensions
Instant. Opens in seconds
No sign-up. Just open it
100% free. No limits on use

What you get for a .UST 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.

01

Drop your .UST file

Choose it or drag it in. It's read right here in your browser.

02

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.

03

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 .UST file?

Plain text that programs, servers and people write every day.

A .UST file is a user theme file exported from WiFi SiStr, a software utility developed by DNsoft. These settings files function as plugins that modify the visual appearance of the application's interface. They are primarily opened and managed within the WiFi SiStr program.

Programs that open .UST files

Windows
WiFi Sistr
.UST format details
DeveloperDNsoft

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Frequently asked questions

Is my .UST 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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