Your browser does the work
When you open DigiCompress, your browser downloads the page and the compression code, just as it downloads any website. From then on, compression happens on your computer or phone. When you pick a file, the browser reads it from your disk into memory that belongs to this one tab. Nothing is sent back to us.
Think of it like a calculator app versus asking someone else to do the sum: we hand you the tool; you use it on your own device.
Every file is checked before it’s touched
File extensions are just labels, and anyone can rename “virus.exe” to “report.pdf”. Real files begin with a few identifying bytes — a signature, sometimes called “magic bytes”. A PDF begins with %PDF, a PNG with a fixed eight-byte header, an MP4 with an “ftyp” box.
DigiCompress reads those first bytes and only proceeds if they match a supported format. If they don’t, the file is rejected with a clear message. This protects the compressor from malformed files and stops you from wasting time on a file that can’t be processed.
Compression runs in a background worker
The heavy lifting happens in a Web Worker: a separate thread your browser runs alongside the page, so the interface stays responsive. Images, PDFs and Office documents are handled with well-established open-source libraries. Video and audio use a WebAssembly build of FFmpeg, served from our own domain rather than a third-party CDN.
Our site also sends strict security headers, including a Content Security Policy that only allows code from our own domain. That means the page can’t quietly load scripts from elsewhere.
Purged after download
Once you download the result — or discard it — DigiCompress releases its references to both the original and the compressed file, revokes the temporary download link the browser created, and resets the worker. The compressor shows this as the final Purged step so you can see it happen.
Your browser’s own memory management reclaims the space after that. Closing the tab clears everything immediately.
What we log
To keep the free limit fair and to understand which tools people use, DigiCompress records anonymous, file-free facts:
- File category and detected format — for example “image” and “png”
- Size before and after, the compression level chosen, processing time, and whether it succeeded
- Whether the result was downloaded and purged
- An anonymous random visitor ID kept in your browser’s local storage, and a session ID
- Approximate country and city derived from your IP address at the network edge, plus a salted hash of the IP for abuse limits
- Device type, browser and operating system family, page views and time on page
What we never see
- Your file’s contents, or any part of them
- The file name or folder it came from
- A hash or fingerprint of the contents
- Metadata inside the file, such as photo location or document author
- Your raw IP address in our database
Check it yourself
You don’t have to take our word for it. Open your browser’s developer tools, switch to the Network tab and compress a file. You’ll see small requests carrying anonymous counts — and no request large enough to carry your file. Read the privacy policy for the full detail, or go straight to the PDF compressor.