Dual Subtitles & AI Translation - InterSub

Name: Dual Subtitles & AI Translation - InterSub
Rating: 3.85 (20 reviews)
Author: InterSub

Language learning with dual subtitle translator dualsub to immersive translate meaning of words: Spanish to English, to Japanese etc

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Features & Capabilities

InterSub turns every video into a language classroom. This Chrome extension delivers dual subtitles with real-time AI translation, hover word meanings, and an integrated AI Language Buddy to explain slang, grammar, and usage without leaving the screen. It works across popular streaming sites and platforms, making content more accessible and engaging for learners.

Key capabilities include instant translations across multiple languages, auto-generated captions when tracks are missing, vocabulary saving with AnkiDroid sync and Excel export, RTL language support, and flexible pricing. With support for 30+ languages and platforms like Netflix, YouTube, Prime Video, Crunchyroll, and Coursera, InterSub helps learners at all levels turn viewing into active study.

User Growth & Download Statistics

Add-on Education AI Developer Tools

By:

Daily users:

Rating:

Version:

4.46.0 Last updated: 2026-05-16

Version code:

6264578

Creation date:

2023-12-22

Risk:

Permissions:

Host permissions:

<all_urls>

Content scripts matches:

*
*.newplayjj.com
*.thealloha.club
*.pljjalgo.online
*.allarknow.online
*.online-serial.com
*.algonoew.online
*.stloadi.live
*.lordfilm64.com
*.primevideo.com

Size:

2.47MB

Email:

su*****@intersub.cc

URLs:

Website ,Privacy policy

Full description:

Source:

Firefox Add-ons Store

Data ingested on:

2026-06-15

Compare stats and ranking:

Ranking

# 2,831 ▼ 3

Other rankings

#111 in Language Support ▲ 1

#18 in translations keyword 78 ▲ 1

#69 in ai keyword 89 ▼ 1

#70 in learn keyword 22

#113 in insert keyword 34

Upgrade to see more rankings

Other platforms

Dual Subtitles & AI Translation - InterSub (v4.46.0)

20,000 4.57

(214)

Dual Subtitles & AI Translation - InterSub (v4.46.0)

19,446 4.90

(96)

For Developers

Monetize with App Pass Boost with Extension Booster

Contact the developer

Chrome-Stats does not own this Firefox add-on. Please use these information below to contact the Firefox add-on developer.

Developed by:

InterSub

Firefox Add-ons Store

https://addons.mozilla.org/firefox/addon/intersub/

Email:

su*****@intersub.cc

Website:

https://discord.gg/nCeeFuwjqB

Permission Change History

2025-09-15: Version 4.25.0 → 4.27.0

Add Host permissions: <all_urls>

Add Permissions: identity

Remove Permissions: <all_urls> https://app.intersub.cc/*

2025-08-21: Version 4.23.0 → 4.25.0

Add Permissions: webRequest <all_urls>

Remove Permissions: https://analytics.google.com/* https://hls.ted.com/* https://*.nflxvideo.net/* https://*.2sub.net/* https://*.2sub.movie/* https://*.2sub.pro/* https://*.voidboost.com/* https://*.pv-cdn.net/* https://*.udemycdn.com/* https://cr-play-service.prd.crunchyrollsvc.com/* https://*.ororo-mirror.tv/* https://*.crunchyroll.com/* https://api-edge.cognitive.microsofttranslator.com/* https://edge.microsoft.com/* https://translate.googleapis.com/* https://translate.google.com/*

2025-05-27: Version 4.13.0 → 4.15.0

Add Permissions: https://app.intersub.cc/*

Remove Permissions: https://*.intersub.cc/*

2025-05-08: Version 4.10.0 → 4.12.0

Add Permissions: https://*.2sub.net/*

2025-02-17: Version 3.105.0 → 3.109.0

Add Permissions: unlimitedStorage https://api-edge.cognitive.microsofttranslator.com/* https://edge.microsoft.com/* https://translate.googleapis.com/* https://translate.google.com/*

2024-12-14: Version 3.92.0 → 3.94.0

Add Permissions: https://*.crunchyroll.com/*

2024-12-08: Version 3.91.0 → 3.92.0

Add Permissions: https://*.ororo-mirror.tv/*

2024-12-02: Version 3.87.0 → 3.88.0

Add Permissions: https://*.2sub.pro/*

2024-11-21: Version 3.82.0 → 3.87.0

Add Permissions: https://cr-play-service.prd.crunchyrollsvc.com/*

2024-09-24: Version 3.67.0 → 3.70.0

Add Permissions: https://*.udemycdn.com/*

2024-04-01: Version 3.39.0 → 3.41.0

Add Permissions: https://*.pv-cdn.net/*

2024-03-21: Version 3.33.0 → 3.38.0

Add Permissions: https://*.intersub.cc/* https://*.2sub.movie/* https://*.voidboost.com/*

Remove Permissions: https://app.intersub.cc/*

2024-02-07: Version 3.22.0 → 3.29.0

Remove Permissions: scripting

2024-01-22: Version 3.20.0 → 3.22.0

Add Permissions: https://hls.ted.com/* https://*.nflxvideo.net/*

User Reviews

Users like the add-on for broad site support and helpful dual subtitles with translations, especially for language learning. However, recurring issues include unreliable subtitle loading, inconsistent performance across videos and platforms, onboarding friction due to credit-card requirements, incomplete support on some services (like Amazon Prime), and limited customization with some UI/navigation quirks.

Pros

Broad compatibility across sites (works on Netflix, YouTube, HBO Max and others).
Dual subtitles with translations and automatic translation features.
Helpful for language learning, especially English.
Customizable subtitle behavior and settings.
Enhances viewing of original-language content.

Cons

Subtitles sometimes fail to load or translate, reducing usefulness.
Reliability is inconsistent and the extension can stop working across videos.
Dashboard access requires entering credit card information, which deters usage.
Not all advertised platforms work (e.g., Amazon Prime) and some site support is incomplete.
Limited customization options (fonts/backgrounds) and navigation quirks (arrow-key controls, auto-pause).

Recent reviews

Все працює, рекомендую. Особливо сподобався ШІ переклад на українську мову з англійської. Everything works, I recommend it. I especially liked the AI translation into Ukrainian from English.

by Le*****, 2026-05-03

I think this is the best extension to learning language in firefox.

by Fi*****, 2026-04-17

I hope the pop-up bubbles can be fewer, also, hope every pop-up has a keyboard hotkey to close them, or at least has bigger button to close them. Now, here is the good side, the extension indeed works great for Netflix, HBO Max and YouTube.

by Fi*****, 2026-01-27

View all user reviews ›

Is Dual Subtitles & AI Translation - InterSub Safe?

Risk impact

Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypassing your security settings, and accessing your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.

Dual Subtitles & AI Translation - InterSub requires a lot of sensitive permissions. Exercise caution before installing.

Risk impact analysis details

Critical Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
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Risk likelihood

Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Add-ons Store, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on.

Dual Subtitles & AI Translation - InterSub is probably trust-worthy. Prefer other publishers if available. Exercise caution when installing this add-on.

Risk likelihood analysis details

High This extension was recently updated in the past month. New updates may not be stable or safe.
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Low **** ********* *** ***** **** **** * ****** **** ***** ********** *** **** ****** ** ** ****** *** *****
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