Firefox · Zen · LibreWolf · Floorp · Waterfox
A speed reading extension for Firefox and every Firefox-based browser.
JK RapidReader is a free extension for reading and keeping what you read: RSS feeds, saved articles, PDFs and books, speed reading one word at a time, Read to Me, summaries, quizzes and AI chat. One install from Firefox Add-ons works in Firefox and the browsers built on it.
Free. No account. Firefox 140 or later on a desktop computer; not Firefox for Android. Using Chrome, Edge or Brave? See the Chrome version.
Which browsers
- Firefox: install from Firefox Add-ons.
- Zen: Firefox Add-ons. Coming from Arc? Bring your library.
- LibreWolf: Firefox Add-ons; read the note on clearing data when it closes.
- Floorp and Waterfox: Firefox Add-ons.
They all get the same features as the Chrome version, with one difference: where your library is kept.
Where your library lives
Firefox does not let an extension open a folder on your computer. So on the first run, RapidReader offers Keep in This Browser: your library is the same set of files as in Chrome (each article a Markdown file, with its notes, chats, quiz and flashcards), kept in the browser’s own storage on your computer. RapidReader asks the browser to keep that storage, and Firefox agrees without asking you.
It is not synced and you cannot open the files in Finder or a notes app while they are there. Integrations → Data Management → Download Library saves the whole library as one zip, any time: keep it as a backup, unzip it into an Obsidian vault, or move it. Load Library brings a library zip in, from another browser or computer. Download a copy before you uninstall the extension or reset the browser.
Firefox
Open the Download page, click Add to Firefox, then Add. Click the JK RapidReader icon (under the Extensions button, the puzzle piece, if you don’t see it) and choose Keep in This Browser. The first time RapidReader fetches a web page for you, Firefox asks you to allow it; you can change that later in about:addons. Private windows may have no storage for a library.
Zen
Zen installs from Firefox Add-ons exactly as Firefox does, and keeps the library in the browser. If you are moving from Arc, your Arc library comes with you: moving from Arc to Zen has the steps.
LibreWolf
LibreWolf installs from Firefox Add-ons like Firefox. It is set up for privacy and, by default, clears cookies and site data when it closes. Whether that touches an extension’s own storage depends on your settings, so treat the library kept in the browser with care: Download Library after a reading session, and if the library is ever empty after a restart, Load Library brings it back from your last zip.
Floorp
Floorp installs from Firefox Add-ons like Firefox, and keeps the library in the browser.
Waterfox
Waterfox installs from Firefox Add-ons like Firefox, and keeps the library in the browser.
Questions
Is it the same as the Chrome version?
Yes: the same reading, listening, feeds, library, quizzes, notes and AI chat, from the same code. Only the place the library is kept differs.
Can I use free, local AI in Firefox?
Yes, with Ollama. Set OLLAMA_ORIGINS to chrome-extension://*,moz-extension://* and restart Ollama; that one setting covers both browsers. Ollama setup.
Can I keep my library in Obsidian?
Download Library gives you the Markdown files to put in a vault, but edits made there do not flow back while the library is kept in the browser. For a live vault, use RapidReader in Chrome, Edge, Vivaldi or Arc with a folder inside the vault.
Does it work on Android?
No. JK RapidReader is for desktop and laptop computers.