# Dual Subtitles & AI Translation - InterSub

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

Canonical page: [https://chrome-stats.com/d/intersub](https://chrome-stats.com/d/intersub)

## Overview

- **ID:** `intersub`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** InterSub
- **Category:** appearance,language-support
- **Daily users:** 1,441
- **Weekly downloads:** 153
- **Rating:** 3.85 / 5 (20 ratings)
- **Version:** 4.50.0
- **Last updated:** 2026-08-31
- **First published:** 2023-12-22
- **Size:** 2.49 MB
- **Data as of:** 2026-09-06
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/intersub/)
- **Website:** [https://discord.gg/nCeeFuwjqB](https://discord.gg/nCeeFuwjqB)
- **Privacy policy:** [https://addons.mozilla.org/firefox/addon/intersub/privacy/](https://addons.mozilla.org/firefox/addon/intersub/privacy/)

## Description

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.

## Rankings

- #2,727 — Overall
- #110 — Language Support
- #18 — translations
- #74 — ai
- #93 — learn
- #115 — insert

## Permissions and access

### Permissions

- `storage`
- `identity`
- `unlimitedStorage`
- `webRequest`

### Host permissions

- `<all_urls>`

### Content script matches

- `*`
- `*.newplayjj.com`
- `*.thealloha.club`
- `*.pljjalgo.online`
- `*.allarknow.online`
- `*.online-serial.com`
- `*.algonoew.online`
- `*.stloadi.live`
- `*.lordfilm64.com`
- `*.primevideo.com`
- `*.amazon.com`
- `*.amazon.co.uk`
- `*.amazon.de`
- `*.amazon.co.jp`
- `www.bilibili.tv`
- `www.biliintl.com`
- `*.crunchyroll.com`
- `*.disneyplus.com`
- `*.brightline.tv`
- `*.cinemax.com`
- `*.discomax.com`
- `*.forthethrone.com`
- `*.hbo.com`
- `*.hboasia.com`
- `*.hbogo.co.th`
- `*.hbogo.com`
- `*.hbogo.eu`
- `*.hbogoasia.com`
- `*.hbogoasia.hk`
- `*.hbogoasia.id`
- `*.hbogoasia.ph`
- `*.hbogoasia.sg`
- `*.hbogoasia.tw`
- `*.hbomax.com`
- `*.hbomaxcdn.com`
- `*.hbonow.com`
- `*.max.com`
- `*.maxgo.com`
- `kino.pub`
- `*.netflix.com`
- `*.ororo.tv`
- `*.2sub.net`
- `*.2sub.movie`
- `*.2sub.pro`
- `*.yohoho.tv`
- `*.youtube.com`
- `youtube.com`
- `youtu.be`

## Safety

- **Risk impact:** Very high risk impact
- **Risk likelihood:** Moderate risk likelihood

### Analysis details

- Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
- This extension was recently updated in the past month. New updates may not be stable or safe.

> Some risk analysis details are omitted from this free response. [Upgrade to view the full analysis](https://chrome-stats.com/pricing).

## Review summary

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).

## Similar extensions and apps

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- [DuSubs: Dual Language Subs](https://chrome-stats.com/d/dusubs) — 5 users
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- [EasySubs](https://chrome-stats.com/d/easysubs) — 189 users, 3.88 / 5
- [FluentAI: Dual Subtitles for Netflix & more](https://chrome-stats.com/d/fluentai-language-learning) — 37 users, 3.00 / 5
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- [Sublern — AI Translate Words in Video Subtitles](https://chrome-stats.com/d/sublern) — 174 users
- [Dualsub - YouTube Subtitle Translator](https://chrome-stats.com/d/dualsub) — 4,964 users, 4.25 / 5
- [EasyDualSub - Merge & Watch Dual Subtitles](https://chrome-stats.com/d/easydualsub-merge-subtitles) — 64 users, 5.00 / 5
- [Subtiltée: Dual Subs (Netflix, YT & Any Site)](https://chrome-stats.com/d/subtilt%C3%A9e-dual-subs-any-site) — 2 users
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- [VoxSub](https://chrome-stats.com/d/voxsub) — 13 users, 5.00 / 5

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Source: [Chrome-Stats](https://chrome-stats.com/d/intersub)