Offline PDF Compressor

Modern browsers cache the page assets, and the compression logic itself is WebAssembly — compiled code that executes locally on your CPU, exactly like a native desktop application. Once the tab has loaded, every subsequent operation is a local computation with no network dependency.

Open your browser DevTools, switch to the Network tab, and compress a file: you will see no outbound request carrying your document. For an even stronger guarantee, disable your network adapter entirely and confirm the tool still produces a compressed file.

The architecture is designed for exactly that: your data never crosses a network boundary, which sidesteps most GDPR, HIPAA and internal data-residency concerns around third-party processing. That said, always confirm against your own organisation-specific policy before handling classified material.

Not while it is encrypted. A protected PDF has its content streams encrypted, so the compressor cannot read the images it needs to optimize. Remove the password in your PDF reader first, compress, then re-apply protection to the smaller output if you still need it.

It depends on the content. Scanned or image-heavy documents commonly shrink by 70–95%. Text-only PDFs that were already optimized may only drop 5–20%, since there is little redundant data left to remove.

Page dimensions, margins and layout are always preserved exactly. Print appearance only changes if images are downsampled below your printer's resolution. Less Compression holds images near 200 DPI, which prints cleanly on any office printer; avoid Extreme mode for anything going to paper.

Any modern browser with WebAssembly support: Chrome, Edge, Firefox, Safari, Brave, Opera and Vivaldi, on desktop and mobile alike. There is no minimum specification beyond that — older or lower-powered devices simply take longer on large documents.

Progress tracks pages completed, not time elapsed, and pages differ enormously in cost. A page holding one large photograph takes far longer than ten pages of plain text, so the bar appears to stall. It is still working — the Web Worker keeps the interface responsive throughout.

It is gone from the page entirely. The document is held only in the tab's volatile memory during processing and is discarded when the tab closes. Nothing is written to browser storage, no cookie records it, and no copy exists anywhere else — your original stays untouched on disk.

Nothing persists. The compressed result lives in your browser tab's memory until you download it, and everything is discarded the moment you close or refresh the page. There is no server-side copy because the file was never sent anywhere.