ZIP Builder
File
Bundles arbitrary files into one ZIP archive directly in the browser. Files are compressed with deflate (level 6) using the in-page `fflate` library, so nothing is uploaded and the work scales with your machine. Useful when you need to send a few attachments at once but the original tools are on your phone or a locked-down machine.
No files yet — drop or pick a few.
Everything runs in your browser — files never leave your device.
How to use
- Drop files into the upload area, or click to pick them.
- Set the output filename (defaults to `archive.zip`).
- Hit Build, then Download. The size of the archive and the compression ratio are shown after building.
Frequently asked questions
- Are the files uploaded anywhere?
- No. The bundling runs in your browser tab — the files are read, compressed, and offered as a download all locally. Closing the tab discards everything.
- What's the size limit?
- There's no hard cap, but the whole archive is held in memory at once. For mobile that's typically fine up to a few hundred MB; for very large bundles use a desktop tool that streams.
- What about duplicate filenames?
- When two dropped files would share a name inside the archive, the second one becomes `name (2).ext`, the third `name (3).ext`, and so on — same behaviour as macOS Finder and Windows Explorer copy-paste.
- What compression level is used?
- Deflate level 6, the default for most archivers. Higher levels save little extra and would noticeably slow down a phone.
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