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Read Frog vs Language Reactor

Both put dual subtitles on YouTube and Netflix for free. Read Frog also translates the web pages around them and any text you select, runs on Chrome, Edge and Firefox, is open source, and turns the words you save into FSRS flashcards, from $3 a month.

Last updated October 18, 2026

Both put a translation under every YouTube and Netflix subtitle, and in both that part is free. Language Reactor works inside the video and in its own web app: click a word, save it, drill it in PhrasePump or export it to Anki. Read Frog also runs on Edge and Firefox, translates the page around the player and anything you select, and reviews the words you save as flashcards on its own FSRS schedule. Open source; Pro is $3 a month.

Dual subtitles on YouTube, X and Netflix

Open a captioned video, click the Read Frog button in the player, and every line appears with its translation, in sync. It works on regular videos, Shorts and embedded players, on videos posted to X, and on Netflix, with the free Google or Microsoft translator or your own OpenAI, DeepSeek, Gemini or local model. Select a word in the subtitles to look it up and save it.

Feature comparison

Read FrogLanguage Reactor
Dual subtitles on YouTube✓free✓free
Dual subtitles on Netflix✓free✓free with Netflix's own subtitle tracks; machine translation needs Pro
Videos on X (Twitter)✓Not in its feature list
Subtitles for videos without captions✓AI transcription, Pro✓speech recognition for Netflix audio tracks and local files, Pro
Bilingual web page translation✓freeImports text into its own reader instead
Selection translation on any page✓freeNot in its feature list
Dictionary on a subtitle word✓select it✓free pop-up dictionary
AI explanations of words and sentences✓Custom AI Actions, with your own prompts✓Lexa AI dictionary and Aria chat; a stronger model on Pro
Save words with their sentence✓Notebase: 10 notes free, unlimited from Pro✓free in PhrasePump; everywhere on Pro
Spaced repetition review✓FSRS, built in✓PhrasePump drills your due words in sentences; export to Anki on Pro
Your own API key, or local models like Ollama✓Not in its feature list
Open source✓GPL-3.0No
BrowsersChrome, Edge, FirefoxChrome; its web app works on phones

Language Reactor's details come from its website, its Pro page and its Chrome Web Store listing, checked in October 2026.

What Read Frog adds

Beyond the player

Language Reactor's tools live inside Netflix, YouTube and its own web app, where you import the text you want to read. Read Frog carries the same habit to any page, right where it is:

  1. Turn on page translation and the article, thread or documentation around the video reads with the translation beside each paragraph.
  2. Select a word or a long sentence anywhere and run an AI Action: a definition in context, a breakdown of the grammar, or any prompt you write yourself.
  3. Save it to Notebase in one click. Add a card template and your notes become flashcards that FSRS schedules by how well you remember each one, with no export step.

Who each one is for

Read Frog fits you if

  • You use Edge or Firefox, or more than one browser.
  • You read as much as you watch: articles, documentation and X, not only Netflix and YouTube.
  • You want your saved words as flashcards you design yourself, scheduled by FSRS.
  • You want to bring your own API key or run a local model, and read the code that handles your pages.

Language Reactor may fit better if

  • You watch mostly Netflix and want the player tools it has built up: auto-pause, precise playback controls and a catalogue of shows and channels sorted by language.
  • You already live in Anki and want cards with audio and screenshots exported for you.
  • You want speech-recognized subtitles for dubbed Netflix audio or local video files.
  • You want a chat partner and listening drills: its Aria chatbot and PhrasePump.

Pricing

Read FrogLanguage Reactor
Free plan✓✓
MonthlyPro: $3. Ultra: $7Pro: $5.95
YearlyPro: $30. Ultra: $70Pro: $39.95, or $13.95 every three months
TrialNot needed: the free plan has no time limit14-day Pro trial, no card needed

Language Reactor's prices are its US prices with tax included, as shown at checkout in October 2026; other countries see a local price. See what each Read Frog plan includes on the pricing page.

Switching from Language Reactor

  1. 1

    Install Read Frog

    Follow the installation guide. With both extensions on, a video can get two subtitle overlays, so turn on subtitles in only one of them.

  2. 2

    Turn on subtitles

    Open a YouTube video with captions, click the Read Frog button in the player's control bar, and turn on subtitle translation. The settings are described in Video Subtitles.

  3. 3

    Save and review

    Select a word in the subtitles, run an AI Action, and save the result to a notebase. Add a card template and the review schedule starts.

What users say

I watch anime and Japanese vloggers on YouTube, and finding Read Frog felt like discovering a whole new world! A fansub-level experience: Gemini is amazing at filling in what spoken language leaves out, and the subtitles come out natural and colloquial — goodbye stiff machine translation!
FN
Finn Nathaniel
Chrome Web Store
chrome
It doesn't just do immersive translation — it also gives AI companion explanations word by word, sentence by sentence. Language learning effortlessly reaches the next level.
songkeys
songkeys
@songkeys
X
It can translate pages, extract the main content of an article, and give detailed explanations of words and sentences.
阮一峰
阮一峰
ruanyifeng.com

Frequently Asked Questions

If you have more questions, please contact us.

Dual subtitles, free, on three browsers

Read Frog is free to install, and translating captioned videos on YouTube, X and Netflix costs nothing.