Modded versions of 7-Zip that include LZ4 support significantly transform the tool from a high-ratio, slow-speed archiver into a high-performance utility capable of near-instant data processing. While standard 7-Zip excels at making files as small as possible using LZMA/LZMA2, modded versions like 7-Zip-zstd add codecs designed for extreme speed and real-time use. Why LZ4 is Included in Modded 7-Zip

LZ4, developed by Yann Collet, is a lossless compression algorithm designed for speed and efficiency. Its primary goal is to provide fast compression and decompression speeds while maintaining a reasonable compression ratio. LZ4 achieves this through its unique approach to compression, which focuses on finding repeated patterns in data and representing them in a compact form.

7-Zip ZS (by mcmilk) already adds LZ4, LZ5, Zstd, and Brotli to 7-Zip. You can find it on GitHub.

7. Alternative (no modded 7-Zip)

If you don’t want a modded build, use native tools:

Warning 1: Incompatibility with stock 7‑Zip
A .7z archive compressed with LZ4 cannot be opened by the official 7‑Zip. It will throw an “Unsupported compression method” error. Recipients must also use the modded version. If you want cross-compatibility, use .zip with LZ4 (less common) or stick to standard formats.

Is It Safe? Legal?

Since both 7‑Zip (LGPL) and LZ4 (BSD) are open source, modded builds are legal and common. However, they’re unofficial — you won’t find LZ4 in Igor Pavlov’s original branch. Stick to builds from trusted sources to avoid backdoors or broken archives.

Caveats and Limitations (Read Before Switching)

3. Database Backups

If you run a local SQL database or a VM sandbox, dumping the folder to an LZ4 7z file takes seconds, minimizing downtime.

The primary way to use LZ4 within 7-Zip is through a popular fork known as 7-Zip ZS (Zstandard) or by adding the Modern7z plugin to a standard installation. Standard 7-Zip does not natively support LZ4. Overview of 7-Zip ZS (Modded Version)