Privacy Policy

Last updated: October 14, 2026

This policy explains what information Sign4K handles when you use the Sign4K Chrome extension, the Sign4K Academy, Sign4K Talk and the website at sign4k.com (together, “Sign4K”). Sign4K is run by the Sign4K team (“we”, “us”).

1. What the Chrome extension does with your data

To sign a video, the extension has to read its captions. To sign text you select, it has to read that text. Here is exactly what happens:

• Captions and selected text are read and turned into signs inside your browser. They are not sent to us or to anyone else, and they are not saved.
• The extension can run on any website (that's why Chrome says it can “read and change data on all websites”), so that it can sign captioned videos and any text you right-click. It only reads captions and the text you choose. It does not read passwords, forms, messages or your browsing history.
• Saved on your computer only (in Chrome's extension storage): the signer you picked, the words you saved to learn later, and a copy of the sign library.
• One thing goes over the internet: about every 6 hours the extension downloads the latest sign library (sign4k-data.json) from sign4k.com. This is a plain download, like opening a web page. It carries no information about you or what you watch. Like any web server, ours may briefly log the request (see section 4).

The extension's use of information follows the Chrome Web Store User Data Policy, including its Limited Use requirements.

2. Sign4K Academy

The Academy needs no sign-up. Your progress (lessons done, streak, points, saved settings) is stored in your browser's local storage on your device. We can't see it. If you clear your browser data, it is gone.

3. Sign4K Talk

• When you press the microphone, Talk uses your browser's built-in speech recognition. In Google Chrome, this sends your voice to Google to turn it into text, under Google's privacy policy. Other browsers may use their own provider or work on your device. Sign4K does not receive or store the audio.
• When the Deaf person types a reply, it is read aloud with your browser's built-in voice.
• Conversations are not saved. When you close the page, they are gone.
• The microphone only turns on when you press the button, and your browser asks for your permission first.

4. The website

• Server logs. Our host (Namecheap) keeps standard logs when you visit: IP address, browser type, page requested and time. We use them only to keep the site running and secure. They are deleted on the host's normal schedule.
• Fonts. Our pages load fonts from Google Fonts, so Google receives your IP address when you open a page.
• No cookies for tracking. We don't use analytics, advertising cookies, tracking pixels or fingerprinting. The only things saved in your browser are the Academy progress and settings described above.

5. Payments and donations

Paid plans and donations are handled by our payment provider (Stripe). When you pay, you give your name, email, card details and billing country directly to them. We receive your name, email, the plan you bought, the amount and the date, but never your full card number. We keep these records for as long as tax and accounting laws require. Stripe's own use of your data is described in the Stripe Privacy Policy.

6. When you email us

If you write to us, for example to apply for free Pro, become a partner or ask for help, we receive your email address and whatever you tell us. Free-Pro applications may include your country and your situation. We use this only to answer you and decide on your application, we keep it private, and we delete it within 24 months of our last exchange unless you ask us to keep helping you.

7. Who we share data with

We don't sell, rent or trade personal data. We only share it with the services that make Sign4K work (our web host, our email provider and our payment provider), or when the law requires us to.

8. Your rights

Wherever you live, you can ask us to show you, correct or delete the personal data we hold about you, or to stop using it. Write to hello@sign4k.com and we'll answer within 30 days. If you live in the EU, the UK or California, data-protection laws there (such as the GDPR and the CCPA) give you these rights too, and you can complain to your local data-protection authority. Since most data stays on your own device, you can also delete it yourself: remove the extension, or clear your browser's site data for sign4k.com.

9. Children

The Academy is made for learners of every age and doesn't ask anyone for personal information. Paid plans are for adults; a parent or guardian should buy them for a child. If you think a child has sent us personal information, tell us and we will delete it.

10. Security

Our website uses HTTPS. Because the extension does its work on your own computer, there is very little personal data on our side to protect in the first place.

11. Changes to this policy

If we change this policy, we'll update the date at the top of this page. If a change is important, we'll say so on the home page before it takes effect.