Edit & Annotate

Sign PDF

Add a signature to a PDF by drawing it, typing it, or uploading a signature image, then drag it onto the page and resize it to fit. This is a visual electronic signature for approvals and sign-off, not a cryptographic certificate-based digital signature. Runs locally on your SnapOtter instance, so contracts and agreements never leave your network.

Features

  • Draw, type, or upload a signature image
  • Drag to position and resize the signature anywhere on a page
  • Add signatures or initials across one page or many
  • Reuse saved signatures stored locally in your browser
  • Visual electronic signature applied as a non-destructive overlay

What you can do

  • Signing a contract or agreement before sending it back
  • Filling in and signing an onboarding or HR form
  • Placing initials on each page of a multi-page document
  • Signing an invoice without printing and scanning it

Self-hosted. Your files never leave your network.

SnapOtter runs entirely on your own infrastructure. Files processed with Sign PDF are never uploaded to third-party servers. Deploy a single Docker container and process files with full privacy, no watermarks, and no usage limits. Open source under AGPL-3.0.

Frequently asked questions

How do I sign a PDF?
Draw your signature, type it, or upload an image of it, then drag it onto the page and resize it to fit. Everything is processed locally on your SnapOtter instance.
Is this a cryptographic digital signature?
No. SnapOtter adds a visual electronic signature that you draw, type, or upload and place on the page. It does not apply a cryptographic certificate-based digital signature or embed a PKI certificate, so use a dedicated PKI tool if you need a tamper-evident certified signature.
Are my signed documents kept private?
Yes. SnapOtter signs PDFs entirely on your self-hosted instance, so your documents and signatures are never uploaded to an external server or cloud service.

Ready to try Sign PDF?

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