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View a CELX file online, free

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

Drop your .CELX file here

Opens your .CELX file right here.

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Up to 50 MB · 160+ text and code extensions
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100% free. No limits on use

How to open a code or text file online

Three steps, a few seconds, no software.

01

Open your .CELX file

Drop it on the box, choose it from your device, or paste the text straight in.

02

View it instantly

Your .CELX file opens neatly formatted with line numbers.

03

Search, copy or download

Search the text, jump to any line, then copy what you need or download a clean copy.

What is a .CELX file?

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

A .CELX file is a Celestia Script used to automate actions within the Celestia space simulation software. These files are stored in a text-based format and contain instructions for controlling the program's behavior. They can be executed by Celestia or edited using text editors like Notepad and Vim.

Programs that open .CELX files

Windows
Celestia, Windows Notepad
macOS
Celestia
Linux
Vim, Celestia
.CELX format details
DeveloperCelestia Development Team

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Frequently asked questions

Is my .CELX 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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