InkSign handles the everyday cases: signing a lease or offer letter someone emailed you, initialling every page of a contract,
filling in a date, or getting a clean transparent signature image for Word, Google Docs or an email footer. No account, no
upload, no watermark.
1 · Create a signature
- Drawing: every stroke is sampled with its timing (and stylus pressure when available). The pen width follows
your speed (fast strokes are thinner), and each stroke is stored as a smooth filled outline. The result stays vector, so SVG export is lossless.
- Typing: your name is set in one of five handwriting typefaces (SIL Open Font License), with an optional slant.
- Photo / scan: sign on paper and take a photo. Otsu's method picks the paper/ink brightness cut-off automatically.
Brighter pixels fade to transparent, and the ink can be recoloured. The result is then trimmed to the ink.
2 · Sign a document
PDFs are rendered with Mozilla's pdf.js; photos of paper documents are converted to a PDF page. Fields are stored as fractions of the
page as displayed, so they stay put at any zoom. On export they are mapped to PDF coordinates, including pages stored rotated:
rot 0: X = u, Y = H − v
rot 90: X = v, Y = u
rot 180: X = W − u, Y = v
rot 270: X = W − v, Y = H − u (content rotated by rot° to read upright)
The original PDF is modified with pdf-lib: text, links and pages are preserved, and signatures are embedded as images. Name, date and text fields are drawn as real text.
3 · Signing certificate
The optional last page records the signer, the local time with its time zone and the UTC time, every field placed, and the
SHA-256 fingerprint of the original file. Anyone holding the original can recompute the hash to confirm which document was signed.
The fingerprint of the signed file is shown after download.
Is it legally binding?
Many jurisdictions recognise simple electronic signatures for most everyday agreements (for example the US ESIGN Act and UETA, the EU's eIDAS
regulation and UK law), provided the parties intend to sign. Some documents, such as wills, certain property deeds and notarised papers, may
need wet ink, witnesses or a qualified signature.
InkSign produces a simple electronic signature, not a certificate-based (PKI) digital signature. Use a trust-service provider when a
qualified or advanced signature is required. This is not legal advice.
Privacy
Everything runs in this page: pdf.js, pdf-lib and the fonts are served from this repository, and the page makes no network requests with your data.
Saved signatures stay in your browser's local storage. Turn off “Remember on this device” to forget them.