PDFSign
free · MIT · macOS 14+
notarized by Apple

Sign PDFs like Acrobat does. Skip the Acrobat.

PDFSign puts a real cryptographic signature — the same adbe.pkcs7.detached format Adobe Acrobat produces and validates — on your documents. It's a native Mac app that weighs about as much as this web page, and signing PDFs is the only thing it does.

Download for Mac latest release · DMG View the source

no account · no subscription · no telemetry · nothing phones home

§ 1 · The app

Open a PDF, drag a rectangle, sign.

Certificates come straight from your Mac's Keychain — or import a .p12 file. Drop a stamp where the document needs it, or sign invisibly. Encrypted PDFs are refused instead of mangled.

PDFSign showing a consulting agreement PDF with Open, certificate, and Sign controls in the toolbar
The whole interface. There is no page two of menus.
§ 2 · The scribble

Your handwriting, three ways.

01 — TRACKPAD

Draw it

Sign with your finger on the trackpad, like Preview — saved for next time.

02 — PHONE

Scan & sign

Point your phone's camera at a QR code and a full-screen signature pad opens in the browser. Any phone, same Wi-Fi, no app.

03 — PAPER

Import it

Photograph a signature on paper — the light background is lifted away automatically, keeping only ink.

The Sign Document dialog with certificate, placement, and a handwritten signature picker
The resulting signature stamp in the PDF: handwritten scribble next to the signer's name, date, reason, and location
The stamp it leaves: your ink, plus who, when, and why.
Sign on Your Phone dialog showing a QR code and 'waiting for signature' The signature pad as it appears on a phone: Clear and Done buttons and a dashed baseline
§ 3 · The cryptography

Signatures a validator can love.

Signing appends an incremental update — the original bytes are untouched, so signatures already on the document stay valid. What lands in the file: