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 .001 file
001 files come from HJSplit, 7-Zip, WinRAR, 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 .001 file?
Split Archive Part 1 is an archive format developed by various, first appearing in 1995. It is normally produced by HJSplit, 7-Zip, WinRAR.
The first chunk of a file cut into equal pieces. Its own header decides what it really is once the parts are rejoined.
| Full name | Split Archive Part 1 |
|---|---|
| File category | Archives |
| MIME type | application/octet-stream |
| Developer | various |
| Introduced | 1995 |
| Usually created by | HJSplit, 7-Zip, WinRAR |
| OpenAnyFile engine | libarchive WASM engine |
| Opens without upload | Yes — parsed locally in your browser |
Open a .001 file in your browser
OpenAnyFile routes .001 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 .001 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 001 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. Free, and free in the sense that there is no paid tier waiting behind step three.
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 .001 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 001 files
Can I open a .001 file without installing special software?
Yes. OpenAnyFile's libarchive WASM engine runs in your browser, so you can read a 001 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 tell what a .001 file actually contains?
The .001 extension carries no fixed signature, so the extension alone proves nothing. Opening it in OpenAnyFile shows the raw header bytes and detected type, which is the only reliable way to identify one.
Is it safe to open a 001 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 .001 file, exactly?
Split Archive Part 1 — an application/octet-stream format created by various since 1995. The first chunk of a file cut into equal pieces. Its own header decides what it really is once the parts are rejoined.
Does the same viewer handle formats related to 001?
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 .001 file, it will open too: