Does compressing remove selectable text?
Not by default. Recommended works like Acrobat's Reduce File Size: it shrinks and recompresses the images and keeps text, fonts, vector graphics, links and form fields. Only Maximum turns pages into images, so use it for scans or when you need the smallest possible file.
How does the Recommended mode work?
It checks how large each image actually appears on the page, downsamples any image stored sharper than your target and re-encodes it as JPEG. Images it can't handle safely are left alone, and the result is never larger than the original. You'll see how many images were recompressed.
Which level should I choose?
Screen gives the smallest files for reading on screen, eBook is a good middle ground, Print stays sharp on a desktop printer and Prepress keeps the most quality. The presets work in both Recommended and Maximum, and custom settings give you full control.
How much smaller will my PDF get?
It depends on the file. PDFs full of images or saved inefficiently can shrink a lot, while optimized or text-only PDFs may barely change. You'll see the exact size before and after.
Are my files uploaded?
No. Compression runs in your browser with pdf.js, pdf-lib and qpdf (compiled to WebAssembly), so your document stays on your device.
What does the Lossless mode do?
It rewrites and recompresses the PDF's internal streams and linearizes the file, without touching any image. Quality stays identical down to the pixel, but the savings are the smallest of the three modes.
