Sign a PDF Without Uploading It to a Server
This page explains, precisely, what “processed in your browser” means for the PDF signing tool, and how you can verify it yourself.
Open the signing toolHow the tool processes your PDF
The signing tool uses two JavaScript libraries that run entirely in your browser: PDF.js renders your PDF's pages so you can see and work with them, and pdf-lib embeds your signature image into the document and produces the final file you download. There is no document-upload endpoint behind the signing feature — your file never leaves your device to be signed. Choosing a file, drawing or placing a signature, and downloading the result all happen locally.
How to verify this yourself
If you're comfortable with browser developer tools, you don't have to take this on faith. Here's a simple way to check:
- Open the signing tool and open your browser's DevTools (usually F12, or right-click → Inspect).
- Switch to the Network tab and clear its log.
- Choose a PDF, add a signature, place it, and click “Download signed PDF.”
- Look through the requests that fire. You'll see the page's own assets load when you first open the tool (JavaScript, CSS, fonts, and similar), but none of the requests triggered by choosing a file, signing, or downloading will contain your PDF's file contents or your signature image as a request payload.
That distinction matters: a normal page load involves ordinary HTTP requests for the site itself, the same as visiting any website. What we're claiming is narrower and more precise — the signing action itself does not transmit your document.
What we're not claiming
We don't claim “zero data transmission whatsoever” or that this site is “100% secure” — those are absolute claims that don't hold up to scrutiny for any website. Like any site, ours is served over ordinary HTTP requests, and basic request metadata (such as your IP address) is visible to whatever is hosting the site, the same as it would be for any page you visit. As of today, this project has no analytics or advertising integrated — we're saying that plainly rather than leaving it ambiguous. If we ever add a privacy-conscious analytics tool, it will be disclosed in our privacy policy and will not have access to your document's contents.
We also don't hold any certifications, security audits, or compliance badges, and we won't claim otherwise.
A note on browser memory
While your tab is open, your browser keeps your PDF and signature in memory so it can render and edit them — that's an unavoidable and expected part of how any in-browser tool works, including this one. It isn't the same as uploading your document to a server; it's local to your device and goes away when you close or reload the tab.
Frequently Asked Questions
The signing feature has no document-upload API. Rendering, placing your signature, and exporting the final file all happen with JavaScript running in your browser, using PDF.js and pdf-lib. Your document's contents are not transmitted anywhere as part of signing it.
No — be precise about what this claim covers. Loading the page itself still requests ordinary assets like this site's JavaScript, CSS, and fonts, the same as any website. What doesn't happen is a request that contains your PDF's file contents or your signature image.
Not currently. As of today, this codebase has no analytics or advertising integrated. If that ever changes, it will be disclosed and such tools will not have access to document contents — see our privacy policy for how that commitment would be reflected.
Yes, briefly and unavoidably. While your tab is open, the browser holds your PDF and signature in memory so it can render and edit them. That's a normal part of how any in-browser tool works, and it ends when you close or reload the tab.