Privacy & How It Works
Your files never leave your device. Here's exactly how Compressor works.
When you select a file in Compressor, nothing gets uploaded to any server. The entire compression process happens directly in your browser using JavaScript.
No servers. No cloud storage. No data collection. Your file stays on your device from start to finish.
How Compression Works
1
File Reading
Your browser reads your file in 1MB chunks to handle even large files (2GB+) without running out of memory.
2
GZIP Compression
We use the fflate library, which implements industry-standard GZIP compression. The slider controls compression level (1-9), where higher levels take longer but compress more.
3
Download
The compressed data is created as a temporary file in your browser's memory and immediately offered for download. No storage, no tracking.
Technical note: The downloaded file is GZIP-compressed binary data. To use the original file, you'll need to decompress it using tools like 7-Zip, WinRAR, or the built-in decompression on Mac/Linux.
What We Don't Do
Files never touch our servers
We don't save or cache anything
No analytics or user tracking
No sign-ups or personal data
Built With Open Source
Compressor uses fflate, a high-performance open-source compression library. You can inspect our code, verify there are no network requests, and see exactly what happens to your files.
npm: fflate•MIT License•Zero dependencies
Still Have Questions?
Open your browser's developer console (F12) and watch the Network tab — you'll see zero uploads while compressing.
Try It Yourself