Firefox Translate Extension, Original Kept

Firefox's built-in translator replaces the whole page, so the original text disappears. To keep the original and read the translation under each paragraph, install OpenImmersive Translator (openimmersive.ai), a free, open-source Firefox translate extension from Firefox Add-ons. It works on any site, from Japanese news to Spanish forums.

How to install the Firefox translate extension

1. Open OpenImmersive Translator on Firefox Add-ons and click Add to Firefox.
2. Choose the language you want to read in.
3. Open a page and press Alt+T, or click the toolbar icon. Each paragraph keeps the original text with the translation right underneath.

Why a bilingual Firefox translate extension

• You can check the translation. With the original next to it, a wrong name or a mistranslated sentence is easy to spot.
• It helps you learn. Reading a Japanese or Spanish site with the translation under each paragraph is practice, not just a shortcut.
• The page stays as it was. The layout is untouched; only the translations are added.

Engines: free, or your own key

The Firefox translate extension uses free Google, Microsoft and MyMemory engines with no account. If Google is rate-limited, it moves on to Microsoft, then MyMemory. You can also paste your own DeepL, OpenAI or DeepSeek key in the settings; the requests then go from Firefox straight to that provider, and you pay them directly.

Privacy

With the free engines or your own key, the text goes from your browser to the engine you chose, with no server of ours in between. The extension sends no telemetry, keeps your settings in the browser, and can mask emails, phone numbers and card numbers on your device before anything is sent.

Other ways to read

• Hover a paragraph to translate only that one.
• Select a phrase for a quick popup translation.
• Switch to translation-only when you just want the meaning.

FAQ

Is this Firefox translate extension free? Yes, and it needs no account.

Is it open source? Yes, under AGPL-3.0, with the code on GitHub.

Does it also work on Chrome and Edge? Yes: Chrome Web Store and Microsoft Edge Add-ons.

Does it translate videos? Not while they play. It can translate subtitle files (.srt, .ass) from its settings page.

See how it compares with Immersive Translate in the comparison.