Privacy Policy

1. Plain-language summary

PDFStamper is a browser extension that adds stamps, signatures, QR codes, dates, images and watermarks to PDF files. All of that happens locally — inside your own browser, on your own computer. Your documents are never sent to UnProton Labs or to any third party.

This policy explains, in detail, what limited information is involved when you use PDFStamper, where it lives, and the rights you have. We've tried to keep the legalese minimal, but the sections below are the binding terms.

2. Who we are

PDFStamper is operated and published by UnProton Labs. ("UnProton Labs", "we", "us", or "our"), the studio behind a small family of local-first productivity tools. References to "PDFStamper", the "Extension", the "Service", or the "Software" mean the PDFStamper browser extension and any directly associated pages on unproton.com.

For any privacy question, our contact is support@unproton.com. UnProton Labs acts as the data controller for the limited information described in this policy.

3. Scope of this policy

This Privacy Policy applies to:

• The PDFStamper browser extension installed from the Chrome Web Store or any other supported distribution channel; and
• The PDFStamper marketing and legal pages hosted by UnProton Labs.

It does not apply to third-party websites, the Chrome Web Store itself, or any other software you may use alongside PDFStamper. Those services are governed by their own privacy policies.

4. Your documents and stamps

This is the most important section, so we'll be explicit.

• We never receive your files. When you open a PDF in PDFStamper, the file is read and rendered by your browser locally. It is not transmitted to UnProton Labs or to any server we operate or contract with.
• We never receive your stamps or their content. The text, images, signatures, QR payloads, dates, watermarks and positions you create are processed on your device and embedded into the output file on your device.
• Export happens locally. When you save a stamped PDF, the new file is generated in your browser and downloaded directly to your computer. No copy is sent to us.
• We cannot see your documents. Because there is no server in the processing path, it is not technically possible for us to access, read, retain, or recover the documents you work with.

5. What we do and don't collect

5.1 Information we do not collect

• The contents of your PDF documents.
• The stamps, signatures, images, or QR data you add.
• Your name, email address, or any account credentials (PDFStamper has no accounts).
• Your file names, folder paths, or browsing history.
• Precise location data.

5.2 Information that may be processed by third parties

When you install or update PDFStamper, the distribution platform you use (for example, the Chrome Web Store, operated by Google) may collect standard installation and usage statistics — such as install counts, aggregate version adoption, crash reports, and coarse country-level data. This processing is performed by the platform under its own privacy policy, and we receive it only in aggregated, anonymized form (for example, "12,000 weekly active users"). We cannot use it to identify you.

5.3 Information you send us voluntarily

If you email support@unproton.com, we will receive your email address and whatever you choose to include in your message. We use this solely to respond to and resolve your inquiry, and we retain support correspondence only as long as needed for that purpose and our records.

6. Local storage on your device

To make PDFStamper convenient, the Extension stores some data in your browser's local storage on your own device. This data never leaves your machine and is fully under your control. It may include:

• Preferences & settings — such as your selected theme, density, panel width, snap and ruler options.
• Saved templates and stamp recipes — including any custom stamps or .pdfstamp recipes you create.
• Session recovery data — a temporary snapshot of an unsaved stamping session, so you can resume after an accidental close.

You can clear all of this at any time by removing the Extension's site data through your browser's settings, or by uninstalling the Extension. Doing so permanently deletes the locally stored data.

7. Browser permissions

PDFStamper requests only the browser permissions it needs to function, and uses them strictly for stated purposes:

We do not request permissions to read your browsing history, your other tabs' contents, your contacts, or your location. Permission sets may evolve with new features; any addition will be reflected here and disclosed at install or update time by your browser.

8. Third parties

We keep third-party involvement to a minimum:

• Distribution platforms (e.g., the Chrome Web Store) handle delivery and updates of the Extension under their own terms and privacy policies.
• Web fonts on our marketing pages may be served by a font provider; loading a font transmits standard request data (such as IP address) to that provider for the sole purpose of delivering the font. This does not occur inside the Extension's document-processing flow.

We do not sell, rent, or share personal information with advertisers or data brokers. We have no advertising business.

9. Analytics & tracking

PDFStamper does not embed advertising trackers and does not build behavioral profiles of you. Any analytics we may use on our marketing pages are limited to privacy-respecting, aggregate measurements (such as total page views) and are never tied to the documents you stamp. We do not use third-party advertising cookies.

10. Children's privacy

PDFStamper is a general-purpose document tool and is not directed at children under the age of 13 (or the equivalent minimum age in your jurisdiction). We do not knowingly collect personal information from children. Because the Extension does not collect personal information in the first place, this concern is largely moot — but if you believe a child has sent us personal information via support email, contact us and we will delete it.

11. Your rights

Depending on where you live (for example, under the GDPR in the EEA/UK or the CCPA/CPRA in California), you may have rights to access, correct, delete, or port your personal information, and to object to or restrict certain processing.

In practice, PDFStamper holds almost no personal information about you: your documents and stamps stay on your device, and your settings live in your own browser. Where we do hold something — principally support email correspondence — you may exercise these rights by writing to support@unproton.com. We will respond within the time required by applicable law. You also have the right to lodge a complaint with your local data protection authority.

12. Security

The strongest privacy protection is structural: because your documents never leave your device, there is no central store of files for an attacker to breach. For the limited data we do handle (such as support emails), we apply reasonable technical and organizational measures. No method of transmission or storage is perfectly secure, but the local-first design substantially reduces your exposure.

13. International users

UnProton Labs operates as a software studio serving users globally. Because document processing happens on your own device, your files are not transferred across borders by us. Limited information such as support emails may be processed in the country where our service providers operate; by contacting us, you understand that this information may be handled outside your country of residence, with appropriate safeguards.

14. Changes to this policy

We may update this Privacy Policy to reflect new features, legal requirements, or operational changes. When we do, we will revise the "Last updated" date above and, for material changes, provide a more prominent notice (such as within the Extension or on this page). Your continued use of PDFStamper after an update constitutes acceptance of the revised policy.

15. Contact us

Questions, requests, or concerns about privacy? We're a small team and we read every message.

Read the Terms of Service →