Client-side · No uploads
Compress PDF
Two-stage pipeline: lossless structural optimisation, then optional page re-rendering for larger gains. Your PDF is never uploaded — everything runs in your browser.
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Privacy by design. pdf-lib and PDF.js run entirely in your browser via JavaScript / WebAssembly. No file data is sent to any server at any point.
FAQ
Is my PDF uploaded to a server?
No. All compression happens entirely in your browser using WebAssembly and the Canvas API. Your files never leave your device.
What is the difference between Safe Lossless and the other profiles?
Safe Lossless only rewrites the PDF structure (object streams, deduplication) without touching image quality or text. Balanced, Smallest, and Print profiles additionally re-render each page as a JPEG image, which gives much larger size reductions but makes text non-selectable.
Will compression break my digital signatures?
Any rewrite of a PDF invalidates embedded digital signatures. If signature preservation matters, use Safe Lossless and be aware that even structural rewrites may break them.
Why did my file get larger after compression?
Some PDFs are already well-optimized. If Safe Lossless doesn't help, the PDF was probably written with object streams already enabled. Try a lossy profile (Balanced or Smallest) for larger reductions.