Choose Dubstack
You mostly watch Netflix and YouTube and want the smallest learning layer that still handles phrases, replay, blur, and export.
See Dubstack featuresChrome extensions · Compared from current product pages
Choose the subtitle tool that fits how you learn.
Some learners want a complete study system. Others want two dependable subtitle lines and a lookup panel that disappears when they are done.
Checked July 12, 2026. Product features and pricing can change.
The short version
Feature count is not the whole decision.
Language Reactor is the mature toolbox. Trancy covers the broadest mix of video, webpages, PDFs, speaking, and mobile practice. InterSub spans more streaming platforms and centers a wordbook. Dubstack is intentionally smaller: Netflix and YouTube, a quiet player overlay, phrase lookup, and free local learning tools.
Side by side
Four different answers to the same problem.
Use this table as a starting point, then verify any deal-breaking feature on the linked product page.
Swipe the table to compare every column.
| What matters | Dubstack | Language Reactor | Trancy | InterSub |
|---|---|---|---|---|
| Best fit | Focused video learning Two sites, fewer controls | Full learning toolbox Video, catalog, text, and playback tools | Broad translation suite Video, webpages, PDFs, and exercises | Multi-platform wordbook Video lookup and vocabulary review |
| Streaming sites | Netflix and YouTube | Netflix and YouTube | YouTube, Netflix, HBO, Disney+, TED, Coursera, Udemy, and more | YouTube, Netflix, Prime Video, Crunchyroll, TED, Coursera, Udemy, and LinkedIn Learning |
| Dual subtitles on free plan | Included | Included | Included | Included without AI translation |
| Lookup | Word click and drag-selected phrase | Popup word dictionary and sentence tools | Unlimited word and sentence translation on free plan | 15 word lookups per month on free plan |
| Saved vocabulary | Saved lines with context, CSV and Anki export on free plan | Saving words and phrases is a Pro feature | 100 words and 50 sentences on free plan; unlimited in Premium | Automatic wordbook with limited free access |
| Extra study tools | Blur, replay, saved context, concise Premium explanations | Catalogs, text import, flashcards, auto-pause, extensive playback controls | PDF translation, speaking coach, pronunciation, exercises, mobile app | Wordbook, reminders, mobile integrations, AI language buddy |
| Browser coverage | Desktop Chrome | Desktop Chrome | Chrome extension plus mobile app and broader browser support | Chrome, Edge, and Firefox |
| Price shape | Free core; $4 monthly or $29 yearly Premium | Free core plus Pro subscription | Free, Premium, and advanced AI tiers | Free, pay-as-you-go from $1.50, and paid plans |
Sources: Language Reactor FAQ, Language Reactor guide, Trancy pricing, and InterSub plans. Platform and plan descriptions are paraphrased from those pages.
Choose by temperament
The best extension is the one you will leave turned on.
Choose Language Reactor
You want a mature study environment with catalogs, text import, flashcards, and deeper playback controls.
Detailed comparisonChoose Trancy
You also translate webpages and PDFs or want speaking, pronunciation, and mobile learning tools in the same product.
Detailed comparisonChoose InterSub
You need Edge or Firefox, watch more streaming platforms, or prefer a lookup allowance and pay-as-you-go model.
View InterSub featuresWhy Dubstack exists
Narrower by design.
Dubstack does not try to be a browser-wide translator, course platform, speaking coach, or media catalog. That makes it the wrong choice for some learners.
The trade is a quieter interface, no account for the free features, local-first processing, phrase selection, and a caption fail-safe that keeps the site's normal captions visible until both Dubstack lines are ready.