Browser extension · 47 languages
Follow any video in your own language, spoken aloud.
Klarsono dubs the video while you watch it: the original voice fades, the translation speaks. Online courses, conferences, documentaries, live streams — on any video player, and even when there are no subtitles.
- Free with your browser’s voice
- 6 free minutes of HD voice
- no card required
Chrome, Edge and Brave today — other browsers coming soon.
The voice
Hear it before you install it
The same sentence, in seven of the 47 languages, in the HD voice you will hear on your own videos.
Prenons un exemple concret : quand vous l’aurez vu, tout le reste vous paraîtra beaucoup plus simple.
Léa · female voice — generated by Klarsono, unedited.
Where you already watch
- Udemy
- Coursera
- OpenClassrooms
- LinkedIn Learning
- YouTube
- Netflix
- Prime Video
- Disney+
- Twitch
- Vimeo
online courses, tutorials, recorded conferences, documentaries and series, live streams and replays, interviews.
and any video player, even inside an iframe — but not video calls
How it works
Three steps, once and for all
After that, Klarsono starts on its own for the videos you watch.
No key to paste in, no setting you have to change: the defaults are the ones we would use ourselves.
- 01
Install and sign in
The extension adds itself to your browser. A Google account or an email link — never a password.
- 02
Play any video
A course, a conference, a replay. Klarsono looks for subtitles; if there are none, it offers to listen to the soundtrack instead.
- 03
Listen in your language
The voice reads the translation. You choose which voice speaks, how fast, and how much of the original sound remains.
What Klarsono does
A voice, and everything it needs around it
Dubbing a video is not enough: it takes the right voice, at the right pace, and knowing what to do when the video will not cooperate.
Every one of these is in every plan, the free one included. What changes from one plan to the next is the amount of HD voice time.
47 languages, natural voices
HD synthetic voices, not your browser’s robotic one. At least two voices per language, switched while you listen.
The voice stays locked to the picture
From subtitles, it follows the video’s own clock: upcoming lines are prepared in advance, the voice speeds up a little when the translation runs longer than the line, and it follows you when you skip forwards or back.
Even without subtitles
Klarsono listens to the soundtrack, transcribes it, translates it and reads it aloud. A few seconds behind, and the video becomes possible to follow.
A proper mix
Which voice speaks, how fast, and how much of the original sound remains. The controls of a mixing desk, because listening to two voices means balancing them.
On every site
Course platforms, conference sites, intranets, players embedded in a page. Anywhere a video plays.
A timestamped summary
What was said, condensed and easy to place in time. The transcript is already there: the summary costs almost nothing.
It tells you what it sees
Never a button that can only fail. When something is missing, the extension names it and offers what to do next.
Who it is for
Your language should not limit what you can follow
What they have in common: long, dense material, in a language you read less easily than you hear it.
You are taking a course in English
Two hours of subtitles is two hours of reading. Take the course the way it was meant to be taken: by listening to it.
You are training for your work
The best training is in English. Your language should not decide what you are allowed to learn.
You follow your field
Conferences, keynotes, technical channels, documentaries: everything that matters comes out in another language first.
Your team is watching
Internal training, industry conferences, client material. A pool of minutes shared across seats, and a single invoice.
Pricing
Start without paying, carry on if it proves useful
6 free minutes of HD voice when you sign up, then your browser’s voice without limit. The paid plans buy premium voice time, and nothing else.
Free
$0
To try it, then to carry on without paying.
- 6 minutes of HD voice, free once only
- Then your browser’s voice, with no limit and no countdown
- Dubbing of subtitled videos, on every site
- Timestamped summaries for as long as you have minutes left
- No card, and no end date
Essential
Most popular$11.00/month TTC
or $110.00 a year, 2 months free
For a course, or a conference or two a week.
- 2 hrs 30 of HD voice a month
- Dubbing from the soundtrack, even without subtitles
- At least two voices per language, switched as you listen
- Timestamped summaries of what was said
- A top-up when the month runs over
- When the minutes run out, the browser’s voice takes over
Pro
$26.99/month TTC
or $269.90 a year, 2 months free
For watching in another language every day.
- 7 hrs 30 of HD voice a month
- Everything Essential includes
- Summaries outside the allowance — they use none of your minutes
- Priority support
- A top-up when the month runs over
Included in every plan
- All 47 languages, with the source language detected for you
- Every site with a player, iframes included
- Rewatching a video you have already dubbed uses nothing
- Choice of voice, and control of speed and original sound
- Translated subtitles shown on screen, or hidden if you prefer
- The full transcript exported as Markdown
- Your account follows you from one browser to the next
- Audio is never kept, and nothing is listened to without your consent
Klarsono is in beta. The paid plans open shortly — create your account and you will be told when they do, keeping the free minutes you have.
The plans in full — allowances, top-ups and what uses up minutes.
Trust
What we do with what you watch
Almost nothing, and never without telling you.
The extension asks for access to every site because a video player can be anywhere. It reads nothing other than that player.
Nothing is listened to without your consent
Listening to the soundtrack requires explicit permission, which you give once and can withdraw.
Audio is never kept
It is transcribed as it passes, then gone. We keep no copy of it.
No keys on your side
The extension holds no API key: everything goes through our server, which counts your minutes and nothing else.
Your data leaves with you
A full export, and permanent account deletion in one click, from your account area.
The detail, without the jargon: privacy policy.
Questions
What people ask us before trying it
The answers also say what Klarsono cannot do. That is more useful than finding out once you have installed it.
Which sites does it work on?
Udemy, Coursera, OpenClassrooms, YouTube, Vimeo, Twitch, company intranets, and most video players on other sites — including when the video sits inside an iframe. When a page has no player, the extension says so rather than pretending.
Is it only for online courses?
No. Klarsono works on any video that plays in a player: recorded conferences, documentaries, series, live streams, interviews, tutorials. It simply makes the greatest difference on long material — reading subtitles for two hours is exhausting, listening for two hours is not.
What about Zoom, Google Meet or Teams?
No, and we would rather say so plainly. A video call is not a video that plays: it is a real-time stream, with no subtitle track to retrieve and no player to control. Klarsono is built for what is watched, not for what several people are saying to one another.
What if the video has no subtitles?
Klarsono offers to listen to the soundtrack: it transcribes it, translates it and reads it aloud. Expect 2 to 3 seconds behind in live mode, and around fifteen seconds when live mode is unavailable.
What uses up my minutes?
The synthesised voice, mainly, and listening to the soundtrack. Translating subtitles costs nothing. A summary counts as half a minute. And rewatching a video you have already dubbed uses nothing at all: the voice is kept in your browser.
And when I reach the end of my minutes?
On a subtitled video, your browser’s voice takes over, free and without limit: the wall becomes a slope. Your minutes come back on the 1st of the month.
Which browsers?
Chrome, Edge and Brave today — they share the same engine. The others are coming: subtitle dubbing first, then listening to the soundtrack.
Is my audio recorded?
No. It is transcribed on the fly and never kept on our servers. Nothing is listened to unless you have allowed it.
Does it work on a video already in my language?
Dubbing is only of use from one language into another. The summary, on the other hand, works in every case.
What does paying annually change?
You pay for ten months instead of twelve: 2 months free. The allowance stays monthly and resets on the 1st, exactly as it does on the monthly plan — you do not receive a year of minutes at once, and whatever you do not use does not carry over.
Can I leave whenever I want?
Yes. From your account area: a full export of your data, and permanent deletion of the account in one click.
Une autre question ? [email protected] — on répond.
The video already exists. All it lacks is your language.
Free with your browser’s voice. 6 minutes of HD voice to try it, no card required.