Compress PDF Online — Private & Free
DimlyPDF restructures and optimizes your PDF using MuPDF in the browser — deduplicating objects and cleaning the file tree so the download is smaller without re-encoding page content as a blurry raster. Files up to 100 MB are supported, and nothing is ever uploaded to a server.
Frequently asked questions
Will compression make my PDF look worse?
DimlyPDF focuses on structural optimization (duplicate objects, xref cleanup). It does not downsample text or vector art the way aggressive “email PDF” tools often do.
What is the maximum file size?
You can compress PDFs up to 100 MB. Everything runs locally in your browser.
Are files uploaded to your servers?
No. Compression happens entirely on your machine via WebAssembly. We never see your document.
Which PDFs shrink the most?
Files with redundant resources, repeated images, or inefficient xref tables often see the biggest savings. Already-minimal PDFs may only change slightly.