Question 1

Is my PDF uploaded to a server?

Accepted Answer

No. All compression happens in your browser using the pdf-lib library. Your file never leaves your device. You can confirm this by watching your browser's Network tab while using the tool.

Question 2

How much will my PDF shrink?

Accepted Answer

The tool strips embedded metadata and optimizes the internal object structure. Savings vary by file: PDFs with redundant metadata or an unoptimized internal layout can see 10-40% reduction. PDFs that are already optimized or consist mostly of compressed images will see smaller gains.

Question 3

Will the content of my PDF change?

Accepted Answer

No. Only invisible metadata (author, creator, timestamps) and internal structural overhead are removed. Page content, text, images, and layout are preserved exactly.

Question 4

What if the compressed file is larger than the original?

Accepted Answer

This can happen if the original PDF was already tightly optimized. The tool will still let you download both versions, but we recommend keeping your original in that case.

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