B1 Archiver vs Zstandard

B1 Free Archiver creates and extracts archives, with desktop software, an Android app and an online archiver. The desktop application creates B1 and ZIP archives and supports almost 40 formats, including RAR, RAR5 and 7z. The online tool extracts files from B1, ZIP, RAR, 7z and other archive types. On Android, B1 also works as a file manager. The B1 format supports password protection using 256-bit AES encryption, and the desktop archiver checks archive integrity with Adler-32 before unpacking. B1 says files uploaded to its online archiver are deleted a few minutes after the page is closed. Its privacy policy says it does not knowingly collect identifying personal data, though it may collect non-personally identifiable server information such as IP address and browser type. The policy also says app and device usage data, including location and network performance, may be collected for anonymous ad-related use in B1 apps. Support is by email and in English only. B1 is free for personal and commercial use, with no registration.

Zstandard is a lossless compression algorithm for real-time workloads, with controls that let users shift compression speed and ratio in small increments. Its reference implementation includes a C library and a command-line utility that creates and decodes .zst, .gz, .xz, and .lz4 files. The format is stable and documented in RFC 8878; the implementation is available under BSD or GPLv2. For small, related samples, training can produce a data-specific dictionary to improve compression. The same dictionary must be present for both compression and decompression, and the samples need to be correlated; there is no universal dictionary. The project documents builds with Make, CMake, Meson, Visual Studio, Buck, and Bazel, plus installation using vcpkg and Conan. Community bindings and ports are listed for languages including Python, Rust, Java, C#, JavaScript, Go, PHP, and Swift. Zstandard is free, with a free plan, and supports Linux, Windows, and macOS.