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Add Signature
Sign documents with your real signature, in your browser
Skip the mouse-drawn scribble. Add your real handwritten signature to PDFs, JPGs, and PNGs directly in your browser. Snap a photo of your signature on paper, the background is removed automatically, position it on the document, and download. Completely free. No account. No uploads. No tracking.
I needed to sign a PDF one day and did what I always do - photographed my signature, opened it and the PDF in Photoshop, set the layer to Multiply, positioned it and exported as PDF. Got me thinking: why can't I do this in the browser? Client-side? So I built it and published it in case anyone else has the same problem. Free of course.
A bit on how it works for the curious: you can draw the signature, type it, or upload a photo of your real one on paper. The photo route is what I use - it just looks like my actual handwriting. To remove the paper background, the code samples the local paper brightness across a grid in the image and compares each pixel to its local background, so uneven lighting in the photo doesn't throw it off. Anything above an adjustable threshold goes fully transparent, with a soft falloff so the ink edges stay clean. When the signature gets stamped onto the document, it's drawn with a multiply blend - same math as the Photoshop trick from the start of this comment, just running in the Canvas API.
For PDFs the document is rendered with PDF.js and edited with pdf-lib, both loaded from cdnjs. JPGs and PNGs are just Canvas API, no library needed. You can also add text, dates, initials, and reposition everything. Hit the button, file downloads.
The document itself never leaves your browser. No upload step, no server processing it, no accounts, no tracking. The only thing the page fetches from outside are those two JS libraries at page load.
It's part of https://vajba.com where I build small browser tools I wanted to exist. No premium tier. No paywall.
Happy to answer questions about how anything works under the hood. Especially curious if anyone finds a PDF it can't handle - or a signature photo the background removal struggles with.
About Add Signature on Product Hunt
“Sign documents with your real signature, in your browser”
Add Signature was submitted on Product Hunt and earned 3 upvotes and 1 comments, placing #159 on the daily leaderboard. Skip the mouse-drawn scribble. Add your real handwritten signature to PDFs, JPGs, and PNGs directly in your browser. Snap a photo of your signature on paper, the background is removed automatically, position it on the document, and download. Completely free. No account. No uploads. No tracking.
On the analytics side, Add Signature competes within Web App, Design Tools and Productivity — topics that collectively have 1M followers on Product Hunt. The dashboard above tracks how Add Signature performed against the three products that launched closest to it on the same day.
Who hunted Add Signature?
Add Signature was hunted by Martin. A “hunter” on Product Hunt is the community member who submits a product to the platform — uploading the images, the link, and tagging the makers behind it. Hunters typically write the first comment explaining why a product is worth attention, and their followers are notified the moment they post. Around 79% of featured launches on Product Hunt are self-hunted by their makers, but a well-known hunter still acts as a signal of quality to the rest of the community. See the full all-time top hunters leaderboard to discover who is shaping the Product Hunt ecosystem.
For a complete overview of Add Signature including community comment highlights and product details, visit the product overview.
Martin