Sign PDF

Your files never leave your device

FileKit — Free browser-based file tools. No upload, no signup.

Drop files here

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Max 500.0 MB per file·Supports: PDF

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Protect PDF

Add a password to your PDF file to keep it secure

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Add Watermark

Stamp DRAFT, CONFIDENTIAL, or any text across every page

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Flatten PDF

Make a PDF non-editable by flattening all form fields and annotations into static content.

How PDF signing works

FileKit renders your drawn or uploaded signature as a PNG image and embeds it on the selected page using pdf-lib — entirely client-side. No server ever receives your signature or your document.

Your Privacy, Guaranteed

FileKit processes every file directly in your browser using JavaScript and WebAssembly. Your documents, images, and data never leave your device — there is no server upload, no cloud storage, and no account required. What happens in your browser stays in your browser.

100% client-side processing
No server upload — ever
No account or signup needed
Works offline after first load