Are my files uploaded to a server?

No. Processing happens entirely in your browser. You can verify it: open your browser's network tab — no file data leaves the page.

Is there a file size limit?

Processing runs on your device, so the limit is your device's memory. Desktops handle hundreds of megabytes; phones are more constrained.

Once the page is loaded, the tool works without a connection — nothing is sent anywhere.

Yes. All strictpdf tools are free with no sign-up.

Shrink a PDF's file size — in your browser, nothing uploaded.

Are my files uploaded to a server?: No. Processing happens entirely in your browser. You can verify it: open your browser's network tab — no file data leaves the page.
Is there a file size limit?: Processing runs on your device, so the limit is your device's memory. Desktops handle hundreds of megabytes; phones are more constrained.
Does it work offline?: Once the page is loaded, the tool works without a connection — nothing is sent anywhere.
Is it free?: Yes. All strictpdf tools are free with no sign-up.