PDF Signature Library

Sign PDFs and add encryption

The Pdftools SDK makes adding signatures to PDFs easy. The SDK supports various types including approval, certification, and time-stamping. It offers robust validation tools, and allows customizable visual appearances. The encryption feature caters to diverse document security needs.
👇 Start Building with the free PDF SDK Experience Edition (in under 60 seconds)
See documentation
Also available via Nuget (.NET) and Maven (Java) package managers
MacOS
Windows Client
Linux

Need a full license key? Contact us
See all Pdftools SDK code samples
6,000+ companies already love Pdftools

PDF Excellence: No Watermarks, Full Support

Enjoy watermark-free results, and connect with exceptional support. Experience Pdftools—where your unique needs meet tailored pricing quotes.
Swift document processing, no watermarks
Swift document processing, no watermarks
Unlock exceptional support—connect with the Pdftools team
Unlock exceptional support—connect with the Pdftools team
Get a pricing quote tailored to your specific requirements
Get a pricing quote tailored to your specific requirements

Why Pdftools

Daily efficiency

We power the daily processing of millions of documents, a testament to our efficiency.

Industry trusted

Pdftools is the preferred choice of leading healthcare, insurance, and legal companies, as well as governments worldwide.

Raving reviews

Our SourceForge rating highlights Pdftools’ exceptional performance and features.

Join our Discord community

Join our Discord community

Connect on our Discord channel for expert support from Pdftools engineers.

Ready to take the next step?

Join 6,000+ customers using Pdftools and take control of your document management.