How to open a code or text file online
Three steps, a few seconds, no software.
Open your .UI file
Drop it on the box, choose it from your device, or paste the text straight in.
View it instantly
Your .UI 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 .UI file?
Plain text that programs, servers and people write every day.
A UI file is a Qt Designer user interface file, an XML description of a GUI form or dialog for a Qt Widgets application. Open it with Qt Creator (the official Qt IDE) for visual editing, or with any text editor to inspect the XML. The file is never deployed at runtime; the Qt uic compiler converts it to C++ at build time.
Programs that open .UI files
| Full name | Qt Designer User Interface File |
|---|---|
| Developer | The Qt Company (originally Trolltech; previously Nokia; now The Qt Company) |
| First released | ~1999 (Qt Designer introduced with Qt 2.x) |
| Category | Text & Code |
| MIME type | application/x-designer |
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Every viewer is free to use.
Frequently asked questions
Is my .UI 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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