Opening RAR and 7Z Files in the Browser: 14 New Archive Tools, Zero Uploads

Most "unzip online" sites make you upload your archive to a stranger's server. The new archive family on Loona Developer Tools does the opposite: everything runs locally in your browser with libarchive compiled to WebAssembly — files are never uploaded anywhere.

What shipped (14 new tools, 37 total on the site)

Extractors — RAR, 7Z, TAR, TAR.GZ, GZ, ISO and a universal extractor that detects the format from the file itself. Each one lists the archive's contents, lets you download single files, or repacks everything as a ZIP.

Converters — RAR to ZIP, 7Z to ZIP, TAR to ZIP, TAR.GZ to ZIP and ZIP to TAR.GZ.

Creators — a TAR File Creator with a hand-written ustar writer, and a GZIP Compressor built on the browser's native CompressionStream.

How it was tested

110 automated checks, and the fixtures were real: Python-built ZIP/TAR/TAR.GZ/TAR.BZ2/TAR.XZ archives, a real .7z written by py7zr, a real ISO9660+Joliet image, and genuine RAR4 and RAR5 files from libarchive's own test corpus — extracted contents verified byte-for-byte. The hand-written TAR writer was validated by reading its output back with Python's tarfile, including a 207-character path that exercises the ustar prefix-split logic.

Honest limits, printed on every page

RAR can be opened and converted from, but never created — the format is proprietary and there is no free encoder. Password-protected archives are detected and refused, not cracked. One engine quirk found during testing: libarchive.js cannot read a raw single-file .gz stream, so the GZ extractor uses the native DecompressionStream as its primary path instead.

The full set lives at Loona Developer Tools — free, no sign-up, and part of a 28-site, 983-page network of on-device tools.