compressO

CompressO (pronounced like "Espresso") is a free, open-source desktop application for shrinking the file size of videos and images. It runs on Mac, Windows, and Linux, and works entirely offline. No files are sent to any server during compression.

The app uses well-known command-line tools under the hood, including FFmpeg for video, pngquant for PNG images, jpegoptim for JPEGs, and gifski for GIF files. CompressO wraps these into a graphical interface so users do not need to know how to run them from a terminal. The screenshots in the README show features for batch compression, trimming and splitting video, embedding subtitles, and updating file metadata.

On the technical side, the app is built with Tauri, a framework that uses Rust for the desktop shell and React for the interface. This keeps the installed app size small compared to alternatives built on Electron. The compression tools ship as bundled standalone binaries for each platform, so nothing extra needs to be installed by the user.

Installation is done through downloadable packages on the GitHub releases page. Mac users can also install via Homebrew. The README notes that macOS will show a warning about the app being from an unverified developer, since Apple requires a paid annual fee to avoid this message. The Homebrew install skips the warning automatically; manual installs require running one terminal command to clear the quarantine flag. On Windows, Microsoft Defender shows a similar caution that can be bypassed by clicking "More Info" and then "Run Anyway."

The project is licensed under AGPL 3.0.