Shinkansen - Blazing fast web & YouTube translator by Jimmy Su
Shinkansen uses AI models to translate web pages and YouTube subtitles. Text is replaced in place to preserve the page layout, and connects directly to the AI model — your data never passes through any third party.
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About this extension
Recent updates:
* Added multi-language translation + multi-language UI: Traditional Chinese / Simplified Chinese / English / Japanese / Korean / Spanish / French / German
* Added Instant Translation — press translate and see the page start turning into Chinese within 1 second (Gemini only)
* Added Bilingual Mode — original and translation displayed side by side
* Added Custom AI Models — connect to OpenRouter / Claude / DeepSeek / local Ollama, and any other model
* Added AI Subtitle Re-segmentation — YouTube auto-generated subtitles are re-segmented by AI for more natural, readable Chinese
* Added Blocked-word list — list of words you don't want in the translation.
* Added Translate Article Opening Only — translate just the first N paragraphs as a preview to save tokens
Features:
* Privacy first — connects directly to Google; no third-party servers in between
* Open source — code is publicly available on GitHub for anyone to audit
* Multi-language translation + multi-language UI — Traditional Chinese / Simplified Chinese / English / Japanese / Korean / Spanish / French / German
Web page translation
• Instant Translation: press translate and see the page start turning into Chinese in 1 second — no waiting for the full API batch to return (Gemini only) • Translated segments are automatically cached; re-translating costs nothing next time
• Two display modes: "Monolingual Overlay" replaces text in place, "Bilingual" shows original and translation side by side
• Edit translations: after translation completes, edit the rendered text directly on the page to fix any awkward translations before exporting to PDF
YouTube subtitle translation
• Real-time translation of YouTube subtitles into Traditional Chinese, matching native YouTube subtitle styling
• AI-powered re-segmentation: auto-generated (ASR) subtitles are re-segmented by AI based on meaning, turning fragmented snippets into readable sentences
• Bilingual subtitles: English + Chinese on two lines simultaneously — great for listening practice
Three translation hotkeys / three engines
• Alt+A / Alt+S / Alt+D each map to a preset translation engine
• Gemini AI (best quality, API key required) • Google Translate (free machine translation, no API key needed, even faster)
• Custom AI Models (OpenAI-compatible — connect to OpenRouter / Claude / DeepSeek / Groq / local Ollama, hundreds of models)
Translation quality controls
• Fixed glossary: force specific terms to always be translated to your chosen rendering (global + per-domain layers)
• Customizable blocked-word list: an editable list of words you don't want in the translation. write your own substitution pairs.
• Document-wide glossary consistency: names and proper nouns translated consistently throughout long articles
• Translate opening only: translate the first few paragraphs as a preview before deciding whether to read the rest — major token savings
Auto-translate and cross-page continuation
• Auto-translate specified sites: add a domain, and pages on that domain are translated on entry
• Cross-tab continuation: when you click a link from a translated page to open a new tab, the new tab is auto-translated and inherits the same preset
Usage tracking and cost-saving reports
• Logs token count, cost, and cache hit rate for every translation, with charts and CSV export
• Two-layer cache (local cache + Gemini implicit context cache); cache hit rate and actual savings are shown in real time after each translation completes
* Added multi-language translation + multi-language UI: Traditional Chinese / Simplified Chinese / English / Japanese / Korean / Spanish / French / German
* Added Instant Translation — press translate and see the page start turning into Chinese within 1 second (Gemini only)
* Added Bilingual Mode — original and translation displayed side by side
* Added Custom AI Models — connect to OpenRouter / Claude / DeepSeek / local Ollama, and any other model
* Added AI Subtitle Re-segmentation — YouTube auto-generated subtitles are re-segmented by AI for more natural, readable Chinese
* Added Blocked-word list — list of words you don't want in the translation.
* Added Translate Article Opening Only — translate just the first N paragraphs as a preview to save tokens
Features:
* Privacy first — connects directly to Google; no third-party servers in between
* Open source — code is publicly available on GitHub for anyone to audit
* Multi-language translation + multi-language UI — Traditional Chinese / Simplified Chinese / English / Japanese / Korean / Spanish / French / German
Web page translation
• Instant Translation: press translate and see the page start turning into Chinese in 1 second — no waiting for the full API batch to return (Gemini only) • Translated segments are automatically cached; re-translating costs nothing next time
• Two display modes: "Monolingual Overlay" replaces text in place, "Bilingual" shows original and translation side by side
• Edit translations: after translation completes, edit the rendered text directly on the page to fix any awkward translations before exporting to PDF
YouTube subtitle translation
• Real-time translation of YouTube subtitles into Traditional Chinese, matching native YouTube subtitle styling
• AI-powered re-segmentation: auto-generated (ASR) subtitles are re-segmented by AI based on meaning, turning fragmented snippets into readable sentences
• Bilingual subtitles: English + Chinese on two lines simultaneously — great for listening practice
Three translation hotkeys / three engines
• Alt+A / Alt+S / Alt+D each map to a preset translation engine
• Gemini AI (best quality, API key required) • Google Translate (free machine translation, no API key needed, even faster)
• Custom AI Models (OpenAI-compatible — connect to OpenRouter / Claude / DeepSeek / Groq / local Ollama, hundreds of models)
Translation quality controls
• Fixed glossary: force specific terms to always be translated to your chosen rendering (global + per-domain layers)
• Customizable blocked-word list: an editable list of words you don't want in the translation. write your own substitution pairs.
• Document-wide glossary consistency: names and proper nouns translated consistently throughout long articles
• Translate opening only: translate the first few paragraphs as a preview before deciding whether to read the rest — major token savings
Auto-translate and cross-page continuation
• Auto-translate specified sites: add a domain, and pages on that domain are translated on entry
• Cross-tab continuation: when you click a link from a translated page to open a new tab, the new tab is auto-translated and inherits the same preset
Usage tracking and cost-saving reports
• Logs token count, cost, and cache hit rate for every translation, with charts and CSV export
• Two-layer cache (local cache + Gemini implicit context cache); cache hit rate and actual savings are shown in real time after each translation completes
Rated 5 by 4 reviewers
Permissions and data
Required permissions:
- Access browser activity during navigation
- Access your data for all websites
Optional permissions:
- Access your data for all websites
Data collection:
- The developer says this extension doesn't require data collection.
More information
- Add-on Links
- Version
- 1.9.8
- Size
- 10.01 MB
- Last updated
- 20 hours ago (May 12, 2026)
- Related Categories
- License
- MIT License
- Version History
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