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View a H3M file online, free

Open and read .H3M files online. View source, logs and text with syntax highlighting, search and line numbers, free.

Drop your .H3M file here

Opens your .H3M 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

What you get for a .H3M 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 .H3M 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 .H3M file?

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

An H3M file is a game map created for Heroes of Might and Magic III. It contains map data, terrain information, and mission parameters used by the game. These files are typically opened with the Heroes 3 Map Editor or the various editions of the Heroes of Might and Magic 3 game.

Programs that open .H3M files

Windows
New World Computing Heroes of Might and Magic 3, Heroes of Might & Magic III: The Restoration of Erathia, Heroes 3 Map Editor
macOS
Heroes of Might and Magic 3
.H3M format details
DeveloperNew World Computing

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Frequently asked questions

Is my .H3M 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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