How to open a code or text file online
Three steps, a few seconds, no software.
Open your .MAFF file
Drop it on the box, choose it from your device, or paste the text straight in.
View it instantly
Your .MAFF 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 .MAFF file?
Plain text that programs, servers and people write every day.
A MAFF file is a web page archive saved by the Mozilla Archive Format Firefox extension, a ZIP file that holds one or more complete web pages with all resources. The extension was discontinued in 2018 and does not work in modern Firefox. To open a MAFF file today, rename it to .zip and extract with 7-Zip, then open the HTML file inside in any browser.
Programs that open .MAFF files
| Full name | Mozilla Archive Format File |
|---|---|
| Developer | Mozilla / third-party (Paolo Amadini, amadzone.org) |
| First released | 2004 (Mozilla Archive Format Firefox extension) |
| Category | Text & Code |
| MIME type | application/x-maff |
| Signature | 50 4B 03 04 "PK" - standard ZIP local file header |
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Frequently asked questions
Is my .MAFF 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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