Privacy policy

Demirline is a Chrome extension that helps you learn languages on YouTube and other web pages. This policy explains what data the extension processes and where it goes.

1. Summary

• Demirline does not create user accounts. Translation text is not sent to a Demirline learning backend.
• Your API key and settings are stored in the browser (chrome.storage.local).
• Text for translation and dictionary lookups is sent only to the AI provider you select.
• The API key is never passed to content scripts or the web page; AI calls run only in the background service worker.

2. Data we store or process

Locally in the browser

• Extension settings (provider, model, target language, hotkeys, UI language, feature toggles)
• The API key you enter
• Notebook entries and review state
• License key, plan, and a random instance id
• Translation cache (to avoid re-requesting the same sentences)

The API key, notebook, and translation cache stay in your Chrome profile. Demirline does not upload them.

Data sent when you use features

• Text to translate (caption sentences, selected words/sentences/paragraphs) — to your chosen AI API
• YouTube caption tracks — read from the watch page (same-origin / Innertube) for dual subtitles; relevant text may be sent to the provider for translation
• Pro license check — the license key and a random instance id go to license.demirline.com; notebook text and the API key do not
• Demirline free translation proxy — if you use the built-in free tier (no API key), the text to translate and a random instance id go to translate.demirline.com, which forwards it to free OpenRouter models. The proxy does not store your text; it only keeps an anonymous daily request counter per instance id.

3. Third-party services

Depending on your settings, requests may go to:

• OpenAI — Privacy
• Anthropic — Privacy
• Google Gemini — Privacy
• OpenRouter — Privacy
• Demirline license — license.demirline.com (key + instance id only)
• Demirline translation proxy — translate.demirline.com (free tier; forwards to OpenRouter free models; text not stored)

Those providers process data under their own policies. Your API key and billing are your responsibility. YouTube is operated by Google; video and caption content are subject to Google’s terms.

4. Permissions

• storage — settings, notebook, license, and cache
• alarms — periodic license refresh
• YouTube host access — captions and page integration
• AI provider host access — translation requests
• <all_urls> content script — for paragraph/word/sentence features only; text is processed when you use the hotkey or selection

5. Sale and advertising

Demirline does not sell your personal data, run an ad network, or include third-party analytics trackers in the extension (this marketing site is kept intentionally simple).

6. Children

The extension is not directed at children under 13. We do not knowingly collect personal data from children.

7. Deleting your data

Removing the extension from Chrome removes its local storage. You can also clear or change your API key in Settings. For provider-side logs, refer to that provider’s policy.

8. Changes to this policy

If features or data flows change, we will update this page and the effective date when material.

9. Contact

Privacy questions: ddenizsalman@gmail.com