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23Brain positions itself as an “AI second brain” learning tool. Rather than simply saving notes or links, it turns scattered content into summaries, quizzes, audio readouts, and a conversational knowledge base. The official workflow is lightweight: copy a post or link, paste the URL into the app, and wait about 2 minutes to generate text and audio summaries. iOS and Android apps are currently available.
Its AI features cover link summaries, screenshot summaries, file summaries, audio summaries, Knowledge Base Chat, unlimited AI conversations, daily quizzes, and on-demand quizzes. The Ultra plan also states support for AI Chat model selection, including ChatGPT 5, Claude Sonnet 4, and Gemini 2.5 Pro. The product leans toward a “learning loop”: collect content first, generate summaries, then use quizzes and chat to support memory and retrieval. The page also mentions content discovery, automatic screenshot discovery, channel subscriptions, Collections, shared Collections, basic/advanced statistics, and more.
Basic is free forever and requires no credit card. It includes 10 link summaries, 5 screenshot summaries, 5 file summaries, 5 audio summaries, 10 on-demand quizzes, 3 Collections, and audio readout. Pro costs $14.99/month and offers a 3-day trial, increasing the summary quota to 100 links, 50 screenshots/files/audio items, while unlocking unlimited Collections, unlimited on-demand quizzes, content discovery, advanced statistics, and more. Ultra costs $29.99/month, further increasing the quota to 300 link summaries and 100 screenshot/file/audio summaries, and adds model selection.
The strengths are its broad input types and a complete combination of summaries, quizzes, chat, and audio readout, making it suitable for turning fragmented information into reviewable learning material. The free plan has a low barrier to entry, and the paid-plan quotas are fairly clear. The limitations are that the page does not disclose privacy or data-processing practices, Chinese-language support, payment methods, API or web capabilities, nor does it demonstrate output quality, citation traceability, or hallucination-control mechanisms. For serious research or enterprise knowledge bases, there is still not enough information to assess trustworthiness.
It is suitable for students, knowledge workers, researchers, content creators, and users who frequently read blogs, YouTube content, files, and audio. Access from mainland China is not stated in the main text. App Store/Google Play availability, payments, and some underlying model services may introduce uncertainty, so we mark it as unknown. If you need alternatives, consider NotebookLM, Readwise Reader, Mem, Notion AI, Recall, Glasp, and similar tools.
⚠ This review is compiled from public sources and does not constitute a purchase recommendation. Verify all facts on the vendor's official site. Verify on 23brain.app official site.
23brain.app is an Unknown AI Apps provider. TG4G tracks its product information, an overall rating of 7.0/10, and a China-accessibility score of Workable. Click "Visit Official Site" to reach 23brain.app directly.