Always Translate от Vladislav Yaroslavlev

Always Translate puts a translate button in the address bar — always visible, on every website, with no guesswork about when the built-in translate icon decides to appear.

How it works:
• Click the button and pick your target language once — the choice is remembered (24 languages available).
• One click translates the entire page in place, with layout, formatting and dynamic content preserved.
• Click again to instantly restore the original text.

Highlights:
• The icon is always visible on every http(s) page — blue = ready, blinking amber = translating, green = translated, red = error.
• Automatic source-language detection; mixed-language pages are translated per paragraph.
• Works on single-page apps: newly loaded content is translated automatically, including open Shadow DOM.
• Code blocks, inputs and editable regions are left untouched.

Privacy: translation is performed by Google Translate’s public service. When you click translate, the page text is sent to translate.googleapis.com and the result is applied locally. Nothing else is collected, stored or transmitted — no account, no ads, no tracking.

Source code (MPL-2.0): https://github.com/vladon/always-translate