Read aloud with synced highlighting
Reads webpages, docs, Kindle pages, and chats aloud with natural AI voices, real-time paragraph or word-level highlighting, and auto-scroll to keep the page in sync.
Overview
CastReader is a Chrome and Edge browser extension that reads webpages, documents, and AI chat responses aloud. It combines text-to-speech with real-time highlighting and auto-scroll so users can follow along on the page while listening.
The product also includes a Read & Explain mode that summarizes pages in the listener’s chosen language while marking key points on the original text. That makes it useful for long articles, foreign-language pages, research papers, ebooks, and chat-based reading workflows where hearing the content is easier than reading it directly.
Core features
Read & Explain mode
Adds an Explain mode that summarizes and unpacks pages in your language while marking the key points on the original text with a moving pen.
Broad page and app coverage
Supports text-to-speech on articles, PDFs, Google Docs, Gmail, Notion, Feishu Docs, Yuque, WeRead, Kindle, ChatGPT, Claude, and more.
Per-response listen buttons
Lets you listen to individual AI responses on supported chat platforms, so you can hear one answer without replaying the whole conversation.
Language and voice options
Supports 40+ languages on the free experience and 100+ premium voices on Pro, with speeds up to 2× free and up to 3× on Pro.
Pro listening extras
Includes cross-device sync and MP3 export on Pro for users who want their listening progress and audio files available beyond one browser session.
Practical use cases
Read long web articles hands-free
Open a long article, newsletter, or forum post and let CastReader read it aloud while the current paragraph highlights and the page auto-scrolls.
Understand difficult or foreign text
Use Read & Explain on dense or foreign-language pages to hear a plain-language explanation while key points are marked on the original page.
Listen to ebooks in the browser
Open Kindle, WeRead, or other supported reading pages in the browser and continue through chapter-style reading with auto-advance.
Follow AI answers without re-reading
Click the listen button on ChatGPT or other supported AI responses to hear a single answer instead of the whole conversation.
Review documents and email by ear
Use the document and email support in Google Docs, Gmail, Notion, Feishu Docs, or Yuque to proofread or review material by ear.
Pros and Cons
Pros
- Combines read-aloud playback with synced highlighting and auto-scroll.
- Works across many content types, including articles, documents, ebooks, and AI chats.
- Read & Explain can present content in the language you know best instead of only reading the original text.
- Free plan includes a usable daily listening allowance plus free explain actions.
- Pro adds unlimited listening and support for long-form reading workflows.
Cons
- Free listening is capped at 20 minutes per day.
- Some advanced listening features, including unlimited listening, premium voices, cross-device sync, and MP3 export, are reserved for Pro.
- The source only shows Chrome and Edge support clearly, so broader browser support is not established here.
FAQ
Is listening free?
Yes. The free plan includes 20 minutes of listening per day with word-synced highlighting and auto-scroll on any page.
What does Pro unlock?
Pro removes the 20-minute daily listening cap and adds unlimited AI explain, 100+ premium voices, up to 3× speed, full ebooks and long PDFs, cross-device sync, and MP3 export.
How many free explains do I get?
The free plan includes 3 explain actions per day, and the counter resets every day.
Which devices or browsers does it support?
It works in Chrome and Edge through the CastReader browser extension, and the subscription follows your account across devices.
Can I cancel anytime?
Payments are processed by Stripe, and the site says you can cancel anytime.
Quick Facts
- Category
- Chrome extension / text to speech
- Platform
- Chrome and Edge
- Primary users
- Readers handling articles, ebooks, docs, and AI chat responses
- Source domain
- castreader.ai
- Pricing shape
- Free plan with optional Pro subscription and 3-day free trial
- Notable workflow
- Listen to text, or use Read & Explain to have pages explained in your language
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