Demirline
Support
Setup, API keys, captions, and hotkeys. If that is not enough, email is enough.
Quick start
- Install Demirline in Chrome.
- Click the extension icon → All settings.
- Select the built-in free tier or paste your API key, set the target language.
- Open a YouTube video with captions and wait a moment for the dual lines.
FAQ
Translation fails / API key error
You can select the built-in Demirline provider to use free translation right away. If bringing your own provider (OpenAI, Gemini, etc.), ensure a valid key and model are selected in Settings, and check your provider balance.
No subtitles appear
The video needs at least one caption track (manual or auto). Refresh the page; YouTube UI changes can cause temporary issues. Try another source language track.
What do the hotkeys do?
Defaults: sentence repeat S; paragraph on any site Alt+T; word Alt+W; sentence Alt+S. Change them in Settings. Some sites may override the same shortcuts.
Is my API key safe?
The key is stored only in browser storage; AI requests run in the background service worker. The page cannot read the key. Still, never share it, and revoke it at the provider if leaked. See the privacy policy.
Which AI models can I use?
The built-in Demirline free tier is available with no configuration. You can also bring your own keys for OpenAI, Anthropic, Google Gemini, and OpenRouter models.
Contact us
If this page does not solve it, email us. Include when possible: Chrome version, error text, video URL (if any), and which provider you use.
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