Are my files uploaded when I compress with PDFWix on Mac?

No. PDFWix's compression runs entirely in Safari/Chrome via WebAssembly — your PDF never leaves your Mac. Verify in Safari's Web Inspector (Develop menu > Show Web Inspector) > Network tab: no upload requests during compression.

What's the maximum file size PDFWix can compress in Safari?

Around 1 GB on a recent Mac with 16 GB RAM, lower on older hardware. For larger files, Split PDF into halves first, compress each, then Merge PDF.

How to Compress a PDF on Mac

A simple step-by-step guide to compress a pdf on Mac using PDFWix's free online tools.

How it works

Open the PDF in Preview — Double-click the PDF in Finder to open it in Preview.
Choose File > Export — From the menu bar, choose File > Export to open the export dialog.
Set the Quartz Filter — In the Quartz Filter dropdown, choose 'Reduce File Size'.
Save the file — Click Save to write the smaller PDF to your chosen location.
Or use PDFWix for quality control — For predictable compression with a quality slider, use pdfwix.com/compress-pdf in Safari.

Frequently asked questions

How do I compress a PDF on Mac without Adobe?

Two free routes. Native: Preview > File > Export > Quartz Filter > 'Reduce File Size' (aggressive, fast, no quality control). Browser: PDFWix at pdfwix.com/compress-pdf gives you Recommended/Strong/Extreme presets and shows before/after sizes. Both run entirely on your Mac.

Does Preview's 'Reduce File Size' still work on macOS Sequoia?

Yes. The Quartz Filter has shipped in Preview since OS X Tiger and remains in macOS Sonoma (14) and Sequoia (15). Apple hasn't changed the filter or removed the feature in any recent update.

Why does my PDF look so soft after using Preview's compression?

Apple's default Quartz Filter downsamples images to about 72 DPI with no quality slider. For better-looking output, either use PDFWix's Recommended preset (150 DPI default) or build a custom Quartz Filter in ColorSync Utility.