Rubi puts the lyrics of the Japanese song you're watching on YouTube right on the video: the Japanese, its romaji reading and an English translation, filling in as each line is sung.
There's nothing to search for or paste. When a video starts, Rubi works out which song it is, gathers the words from the lyrics sites the Vocaloid community keeps, and lines them up with the music.
The video itself, then the original linked in its description (for covers and reuploads), then its title.
Japanese, romaji and English, each from wherever it exists. Songs VocaDB doesn't know come from LRCLIB.
Your own sync first, then the video's captions, then LRCLIB's timed lyrics.
On the video, karaoke style, or beside it, in the singer's colour when Rubi knows who sings.
Not a song? Rubi stays hidden. Vlogs, games and Shorts are left alone, and its button only appears in the player when there are lyrics to show.
Some songs have lyrics but no timing anywhere. Play the video and press S as each line starts. Rubi saves it for that video, and you can share it on LRCLIB so everyone gets it.
In Japanese print, ruby (ルビ) is the tiny reading set over a word so you know how to say it. Rubi does the same for songs, in three layers.
Your settings, your syncs and a cache of lyrics live in the extension's own storage. Uninstalling removes them.
The song's title, artist, length or video ID goes to the lyrics sites. Nothing is sent for videos that aren't songs, or while Rubi is off.
A sync goes to LRCLIB, and a problem report to the developer, only when you press the button. The report shows its full text first.
Last updated: 7 November 2026
Rubi is a browser extension that shows song lyrics on YouTube and YouTube Music. It has no account, no ads and no analytics, and the developer runs no server that receives your browsing.
What stays on your device. Your settings (where lyrics show, which lines, colour theme, on/off), the syncs you make, and a cache of lyrics lookups are stored in your browser's extension storage. They never leave your device unless you choose to share a sync. Uninstalling Rubi deletes them.
What is sent to look up lyrics. When you open a video that looks like a song, Rubi sends the video's ID, title, artist and length to these lyrics services, only to find that song's lyrics and timing: VocaDB (vocadb.net), the Vocaloid Lyrics Wiki (vocaloidlyrics.miraheze.org), LRCLIB (lrclib.net) and Genius (genius.com). Each service handles requests under its own privacy policy. Rubi sends nothing for videos that aren't songs, for Shorts, or while it is switched off.
Sharing a sync (only if you choose to). “Share on LRCLIB” publishes the song's title, artist, album, length and lyrics with your timing to LRCLIB's public database, where anyone can read them. Nothing that identifies you is included.
Problem reports (only if you choose to). “Send report” sends the developer the extension version, the problem type, your comment, the platform, your browser and operating system versions, the video's address and title, what Rubi found, and its technical log for that video. Reports are kept in a Google Form owned by the developer, used only to fix problems, and deleted when no longer needed.
What Rubi never does. It doesn't read your YouTube account, history, comments or any other website, doesn't sell or share data with anyone else, and doesn't use data for advertising or credit decisions.
Contact. Use “Report a problem” in Rubi's popup, and say how to reach you if you'd like an answer.
Japanese songs, with Vocaloid and other synth-voice songs working best, since VocaDB knows them by their videos, covers included. Many J-pop and anime songs work through LRCLIB. English songs show their lyrics too.
Yes. The lyrics show over the player, or in a panel above the player bar, and follow the queue as songs change.
Its lyrics were found, but neither the video's captions nor LRCLIB had timing that matches. You can read along as it is, or sync it yourself with the S key. Then help the community: send your sync to LRCLIB in one click, and everyone who plays that song gets the lyrics in time, in Rubi and in every other player that uses LRCLIB.
If several songs share the name, the 歌 menu lists the others under “Wrong song?”. Otherwise, “Report a problem” in the popup sends the details to the developer in one click.
One switch in the toolbar popup turns Rubi off everywhere, and “Off” hides the lyrics for now while keeping the button in the player.
Yes, with no account and no ads. The lyrics come from community sites; Rubi doesn't host any itself. If Rubi makes your songs better, you can buy its developer a coffee on Ko-fi.