OpenAnyFile
Works
Viewing, inspecting and verifying. You get a browsable listing of everything inside, decompressed in-browser by libarchive compiled to WebAssembly. File details, exact byte size and the detected signature are always shown.
How to open a .bz file
BZ files come from Legacy Unix archives, and the usual advice — buy the software that made it — is rarely what you need just to look inside one. This page covers what the format is and how to open it in a browser tab.
What is a .bz file?
Bzip Compressed File is an archive format developed by Julian Seward, first appearing in 1996. It is normally produced by Legacy Unix archives.
The original bzip, abandoned over patent concerns around its arithmetic coder and replaced by bzip2.
| Full name | Bzip Compressed File |
|---|---|
| File category | Archives |
| MIME type | application/x-bzip |
| Magic bytes (file signature) | 42 5A |
| Developer | Julian Seward |
| Introduced | 1996 |
| Usually created by | Legacy Unix archives |
| OpenAnyFile engine | libarchive WASM engine |
| Opens without upload | Yes — parsed locally in your browser |
Open a .bz file in your browser
OpenAnyFile routes .bz to its libarchive WASM engine, which opens a browsable listing of everything inside, decompressed in-browser by libarchive compiled to WebAssembly.
- Open the OpenAnyFile opener in this browser — nothing to download or sign up for.
- Drag your .bz file onto the drop zone, click to browse for it, or paste it with Ctrl+V.
- The extension is detected and the file is handed to the libarchive WASM engine.
- Your BZ opens on its own viewer page: a browsable listing of everything inside, decompressed in-browser by libarchive compiled to WebAssembly.
- Use fullscreen for a closer look, or download the file back out unchanged. Nothing is transmitted anywhere — the parsing happens in your own browser process.
What you can and cannot do with it here
Does not work
Editing and re-saving. OpenAnyFile is a reader, not an editor — for changes you still need special software or an equivalent.
Local-only by design, not by promise
Plenty of sites promise they delete your uploads. OpenAnyFile avoids the promise by avoiding the upload. When you drop a .bz file in, the browser grants the page temporary read access to those bytes and nothing more — the page has no path to send them anywhere. You can verify it in seconds: open DevTools, switch to the network tab, and open a file. The request list stays empty.
Frequently asked questions about BZ files
Can I open a .bz file without installing special software?
Yes. OpenAnyFile's libarchive WASM engine runs in your browser, so you can read a BZ file with nothing installed. You get a browsable listing of everything inside, decompressed in-browser by libarchive compiled to WebAssembly. For full editing you still need the original application — this is a viewer, not an editor.
How can I check a file really is a BZ file?
Look at the first bytes rather than the extension. A genuine BZ begins with 42 5A. Opening the file in OpenAnyFile shows that signature in the file-details panel, so a file renamed to .bz by mistake is easy to spot.
Is it safe to open a BZ file online?
With OpenAnyFile, yes, because nothing is uploaded. The file is read locally through your browser's File API and never leaves your device, so there is no server copy to leak, log or retain. That matters most for the kind of file people are least willing to hand to a random converter site.
What is a .bz file, exactly?
Bzip Compressed File — an application/x-bzip format created by Julian Seward since 1996. The original bzip, abandoned over patent concerns around its arithmetic coder and replaced by bzip2.
Does the same viewer handle formats related to BZ?
Yes — the same engine also opens .7z, .iso, .rar, so you can compare related files without switching tools.
Related formats
These open with the same engine, so if you have one of these sitting next to your .bz file, it will open too: