# CastReader vs Glasp

CastReader records 55,999 monthly visits with +9.8% month-over-month growth and Freemium pricing. Glasp records 889,564 monthly visits with -14.1% growth and Freemium pricing.

| Metric | [CastReader](https://openaitools.app/tool/castreader) | [Glasp](https://openaitools.app/tool/glasp) |
| :--- | :--- | :--- |
| Website URL | https://castreader.com | https://glasp.co |
| Categories | AI Text-to-Speech, AI Speech Synthesis, AI Reader | AI Research Tool, AI Agent, AI Summarizer, AI Youtube Summary |
| Pricing Model | Freemium | Freemium |
| Monthly Visits | 55,999 | 889,564 |
| MoM Growth Rate | +9.8% | -14.1% |
| Primary Market | United States | United States |
| Direct Visits | 19,699 | 400,603 |
| Review Score | 4.4 | 4.2 |
| Saved Count | 0 | 12 |
| Supported Platforms | Website | Website |

## CastReader

CastReader is built for people who want to consume long-form text with their ears as well as their eyes. Once installed as a Chrome or Edge extension, or opened as an iPhone, iPad or Android app, it reads supported pages and documents aloud using natural AI voices while a word-synced highlight and auto-scroll keep your place. A public Voice Hub lets you preview real voice samples by language before committing, and playback speed ranges from standard rates up to 3x on the paid plan.

What separates it from a plain screen reader is a feature called Read & Explain. Instead of only pronouncing a dense or foreign-language paragraph, CastReader works out what it means and walks you through it in the language you know best, while an animated pen circles and underlines the relevant lines in the original text. That mix of eyes-on-page and ears-on-explanation is aimed at research papers, technical documentation, foreign-language news and other long reads where passive narration is not enough.

Sources are organised into four families: book platforms such as Kindle, WeRead, Google Play Books, Libby, Kobo and O'Reilly; articles and subscriptions including Medium, Substack, The Atlantic, The New Yorker and major newspapers; work documents and email such as Google Docs, Notion, Gmail and Google Drive; and AI conversations from ChatGPT, Claude, Gemini, DeepSeek and Kimi. CastReader also offers private voice cloning for your own documents and a developer Voice API for embedding cloned speech into applications. Free use needs no account, and payments are handled by Stripe.

**Pricing & Plans:** Freemium. Free plan: $0 forever with 20 minutes of listening per day, standard voices up to 1.25x speed, 3 AI explains per day, and 30,000 translation characters per day when signed in. Pro: $4.99/month or $35.99/year (about $3/month, 40% saving) removing the daily listening cap, unlocking full ebooks and long PDFs, more premium voices up to 3x speed, unlimited daily explains, 120 personal-voice minutes per membership month, and 3,000,000 translation characters per month. A 3-day free trial is available; billing is via Stripe.

- **Synced read-aloud:** Natural AI voices narrate webpages, PDFs, ebooks and documents while each spoken word is highlighted and the page auto-scrolls, so you never lose your place.
- **Read & Explain:** Instead of only reading a hard passage, CastReader summarises and unpacks its meaning in the language you know best, with an animated pen marking the key lines in the original text.
- **Wide source coverage:** Works across Kindle, WeRead, Google Play Books, O'Reilly and other book platforms, news and newsletter sites, Google Docs, Notion, Gmail, plus ChatGPT, Claude, Gemini, DeepSeek and Kimi answers.
- **Voice Hub and voice cloning:** Preview real samples of dozens of voices across many languages, and create private cloned voices that Pro members can apply to their own PDF, EPUB, Word and TXT files.
- **Developer Voice API:** A REST API for text-to-speech and private voice cloning in 10 languages, returning MP3 or WAV, priced at $8 per 1M characters for successful generations.

**Strengths:** Combines plain read-aloud with guided explanations that point back at the source text; Covers an unusually broad set of sources, from Kindle and Gmail to ChatGPT and Claude answers; Free tier is genuinely usable with no account required, and the 3-day Pro trial needs no commitment; Personal voice cloning and a pay-per-success Voice API extend it beyond a simple reader

**Limitations:** The 20-minute daily listening cap on the free plan runs out quickly for long books or PDFs; Source support and iOS previews vary by platform, browser version and content access rules; Applying a cloned voice to your own text is limited to 120 minutes per membership month even on Pro

[Profile (Markdown)](https://openaitools.app/tool/castreader.md)

## Glasp

Glasp started from a simple observation: most people highlight things they never look at again. Instead of trapping highlights inside one app, Glasp makes them social. Install the extension, highlight a paragraph on any site or a line in a YouTube transcript, and it lands in your Glasp profile where you can add notes and tags. Because highlights are public by default unless you make them private, a feed of what like-minded people are reading and marking emerges — you can follow other users, see what resonates, and discover sources you would not have found on your own.

Your library becomes the raw material for AI features. Glasp can summarize a long article, a PDF or a YouTube video so you can decide whether it deserves reading, and it can organize what you have already saved into themes. The standout feature is the AI clone: by training on your own accumulated highlights and notes, it produces something that answers in the shape of your interests and reading history. There is also a digital-legacy angle, letting you hand your accumulated knowledge to someone else.

Glasp is free to start, with paid tiers for heavier use and greater AI capacity. Its real niche is learners, researchers, students and content curators who treat annotation as a public, collaborative practice rather than a private bookmark folder — and who want their saved material to do work for them later instead of gathering dust.

**Pricing & Plans:** Freemium. A free tier covers the core highlighting, saving and sharing features with limited AI usage; paid plans add higher AI limits and additional capacity. Check glasp.co for current tier pricing, as it is not published in our listing data.

- **Web and YouTube highlighting:** Mark up passages on any website or lines in a YouTube transcript from a browser extension, then keep them in one searchable library.
- **Social learning feed:** Highlights are shared publicly by default, so you can follow other users, react to their picks and discover sources through people with similar interests.
- **AI summarization:** Generate summaries of long articles, PDFs and YouTube videos to judge relevance fast and to digest what you have already saved.
- **Your own AI clone:** Trained on your accumulated highlights and notes, the AI clone answers in the shape of your reading history and areas of interest.
- **Notes, tags and Kindle import:** Add your own commentary and tags to every highlight, and bring in Kindle highlights so your reading lives in one place.

**Strengths:** Turns throwaway highlighting into a genuinely reusable, searchable library; The social feed surfaces sources through people rather than an opaque algorithm; AI summarization and the AI clone are built on your own saved material, not generic content; Works across web pages, YouTube, PDFs and Kindle imports in one place

**Limitations:** Public-by-default sharing is not for everyone; private lives behind a toggle you have to remember; The AI clone only becomes useful after you have accumulated a real body of highlights; Free-tier AI usage is limited, so heavy summarization pushes you to a paid plan

[Profile (Markdown)](https://openaitools.app/tool/glasp.md)

## Frequently Asked Questions

### How do CastReader and Glasp compare in monthly traffic?

CastReader has 55,999 monthly visits, while Glasp has 889,564. Traffic estimates describe audience size, not product quality.

### How do their growth rates compare?

CastReader has a month-over-month growth rate of +9.8%; Glasp has -14.1%.

### How does pricing compare?

CastReader: Freemium. Freemium. Free plan: $0 forever with 20 minutes of listening per day, standard voices up to 1.25x speed, 3 AI explains per day, and 30,000 translation characters per day when signed in. Pro: $4.99/month or $35.99/year (about $3/month, 40% saving) removing the daily listening cap, unlocking full ebooks and long PDFs, more premium voices up to 3x speed, unlimited daily explains, 120 personal-voice minutes per membership month, and 3,000,000 translation characters per month. A 3-day free trial is available; billing is via Stripe. Glasp: Freemium. Freemium. A free tier covers the core highlighting, saving and sharing features with limited AI usage; paid plans add higher AI limits and additional capacity. Check glasp.co for current tier pricing, as it is not published in our listing data.

## Alternatives

| # | Tool Name | Monthly Visits | MoM Growth Rate | Pricing Model | Summary | Profile (Markdown) |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| 1 | [Notion](https://openaitools.app/tool/t) | 173,441,670 | +0.1% | Freemium | The AI workspace where teams and agents get work done together | [.md](https://openaitools.app/tool/t.md) |
| 2 | [Perplexity](https://openaitools.app/tool/perplexity-ai) | 88,310,223 | -3.7% | Freemium | Real-time AI answer engine and research workspace combining live web citations with frontier reasoning models. | [.md](https://openaitools.app/tool/perplexity-ai.md) |
| 3 | [Speechify](https://openaitools.app/tool/speechify) | 5,457,475 | +0.5% | Freemium | Text to speech and voice AI across every device | [.md](https://openaitools.app/tool/speechify.md) |
| 4 | [SciSpace](https://openaitools.app/tool/scispace) | 4,464,111 | +8.6% | Freemium | Excels at deep scientific literature reading and analysis, whereas Glasp targets general web and video content curation. | [.md](https://openaitools.app/tool/scispace.md) |
| 5 | [Sider](https://openaitools.app/tool/sider) | 2,644,740 | -10.6% | Freemium | Offers a broader multi-model sidebar for quick page summarization, but lacks Glasp's community-driven public highlighting and curation. | [.md](https://openaitools.app/tool/sider.md) |
| 6 | [Luvvoice](https://openaitools.app/tool/luvvoice-free-text-to-speech) | 1,438,923 | -8.2% | Freemium | Free AI text to speech with 200+ voices in 70+ languages | [.md](https://openaitools.app/tool/luvvoice-free-text-to-speech.md) |
| 7 | [Merlin AI](https://openaitools.app/tool/merlin-ai-plugins) | 1,382,634 | +13.1% | Freemium | Provides faster multi-tab AI assistance and article summaries, but lacks dedicated social knowledge curation and note archiving features. | [.md](https://openaitools.app/tool/merlin-ai-plugins.md) |
| 8 | [HARPA AI](https://openaitools.app/tool/harpa-ai) | 537,461 | +99.3% | Freemium | Delivers powerful web automation and page summarization, but features a steeper learning curve than Glasp's streamlined extension. | [.md](https://openaitools.app/tool/harpa-ai.md) |
| 9 | [Peech: Text to Speech Reader](https://openaitools.app/tool/peech-text-to-speech-reader) | 353,093 | -26% | Freemium | Listen to anything. Beautifully. | [.md](https://openaitools.app/tool/peech-text-to-speech-reader.md) |
| 10 | [Scholarcy](https://openaitools.app/tool/scholarcy) | 195,058 | +4.6% | Freemium | Converts academic papers into structured summary flashcards, but lacks Glasp's broad web article and YouTube highlighting capabilities. | [.md](https://openaitools.app/tool/scholarcy.md) |

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Source: https://openaitools.app/compare/castreader-vs-glasp

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