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# ZIP inspector & builder

List what is inside a ZIP before you open it — sizes, ratios, traversal names, nested archives — extract single entries, or build a new archive. fflate runs in a worker; caps are checked against declared sizes before inflating and re-checked against the inflated bytes after.
ZIP file

The signature is read from the bytes — a renamed file that is not a ZIP is refused, not guessed at.
Files to zipBuild ZIP

- No tar, 7z, RAR, or encrypted archives — fflate owns ZIP only, and password-protected entries are refused, not guessed at.
- Nested archives are flagged and never extracted recursively; traversal names are refused, never "cleaned".
- Nothing is uploaded — the archive is read in a worker in your tab.
Nothing in yet

Paste, drop, or type to begin. Everything stays on this device.

drop a .zip to list it, or pick files to build one

## Next door in Files

- [PDF page tools](/files/pdf-pages)
- [Photo metadata](/files/exif)
[All files tools](/files)

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Canonical HTML: https://nutter.tools/files/zip
Markdown version: https://nutter.tools/files/zip/index.md
Plain-text version: https://nutter.tools/files/zip/index.txt
Agent index: https://nutter.tools/llms.txt