Sign PDF Online

Select PDF

Drag and drop your image here or click to select

Max size: 100.0MB

What Is Online PDF Signing?

Online PDF signing lets you add a handwritten signature, stamp, or image to any page of a PDF document without installing special software. Convertilo uses PDF.js for accurate page rendering and pdf-lib for embedding images into the final file. The entire process runs locally in your browser β€” the document never leaves your device.

Technology Behind Our PDF Tools

Our PDF tools are built on two powerful JavaScript libraries that run entirely in your browser:

pdf-lib β€” A library for creating and modifying PDF documents. Used for merging, splitting, and page manipulation operations.
PDF.js β€” Mozilla's PDF rendering engine for parsing and displaying PDF content. Powers our PDF viewer and page export features.
Canvas API β€” Browser's built-in rendering API used for converting PDF pages to image formats (JPG, PNG, WebP) at any resolution.

All operations are performed locally β€” your documents are never uploaded to any server, ensuring complete confidentiality.

Benefits of Online PDF Signing

Freehand Drawing

Draw your signature directly in the browser with a mouse or finger on mobile devices.

Save Signatures

Your signatures and stamps are saved locally for quick reuse on future documents.

Complete Privacy

The document is processed only in your browser β€” nothing is sent to any server.

PDF Signing FAQ

How do I draw a signature?

Click 'Add Signature', select the 'Draw' tab and draw your signature with a mouse or finger. The signature is saved with a transparent background.

What image formats are supported for stamps?

PNG (recommended for transparent background), JPEG and WebP. For best results, use PNG with transparency.

Are my signatures saved?

Yes, signatures and stamps are saved in your browser's local storage (localStorage). They're available on your next visit but don't sync across devices.

Is it safe to sign confidential documents?

Absolutely. The entire process happens locally in your browser. The document never leaves your device.