--- title: I built RiddleBoox: an AI companion that writes back on... description: RiddleBoox is a free, open-source native Android app for BOOX e-ink tablets that lets users write questions with a stylus and receive handwritten AI replies... canonical: https://daily.dev/posts/i-built-riddleboox-an-ai-companion-that-writes-back-on-your-boox-awwtrx3mz twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: I built RiddleBoox: an AI companion that writes back on your BOOX | daily.dev og:description: RiddleBoox is a free, open-source native Android app for BOOX e-ink tablets that lets users write questions with a stylus and receive handwritten AI replies... og:url: https://daily.dev/posts/i-built-riddleboox-an-ai-companion-that-writes-back-on-your-boox-awwtrx3mz og:image: https://api.daily.dev/og/posts/aWWTRx3Mz.png og:image:alt: I built RiddleBoox: an AI companion that writes back on your BOOX og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # I built RiddleBoox: an AI companion that writes back on your BOOX **[OnePercentPlus](https://daily.dev/sources/onepercentplus)** · [@duocnguyen](https://daily.dev/duocnguyen) · 1 min read · 0 upvotes · 0 comments ## Summary RiddleBoox is a free, open-source native Android app for BOOX e-ink tablets that lets users write questions with a stylus and receive handwritten AI replies rendered back in ink. Users bring their own API key for an OpenAI-compatible provider (OpenRouter works out of the box) and can configure agents with custom names, instructions, memory, and access to BOOX context such as library, highlights, and notes. Pages are sent as images to a vision model, keeping the whole interaction handwritten. It requires a BOOX tablet with an active stylus and is available on Google Play, with source on GitHub. ## Content RiddleBoox is a native Android app for BOOX e-ink tablets. Write a question with the stylus, lift the pen, and your selected AI agent reads the page and writes its reply back in ink. The app keeps the conversation on the device and lets each agent have its own name, instructions, memory, and access to BOOX context. A reading agent can work with your library, highlights, bookmarks, and notes. You can also set up a friend, language tutor, or reflection companion. RiddleBoox sends the page as an image to a compatible vision model, so you can keep the interaction handwritten from start to finish. It is free and open source. Bring your own API key for an OpenAI-compatible provider; OpenRouter works out of the box. Requires a BOOX tablet with an active stylus. It is available on Google Play: - Google Play: https://play.google.com/store/apps/details?id=com.riddleboox.app - Website and user guide: https://riddleboox.pages.dev - Source: https://github.com/nguyenvanduocit/RiddleBoox I made this for people who use BOOX as a notebook and want an AI interaction that stays on the page. Feedback from BOOX, e-ink, and Android developers is welcome. ## Similar posts on daily.dev - [Boox finally built the e-reader Kindle Scribe promised but never delivered](https://daily.dev/posts/boox-finally-built-the-e-reader-kindle-scribe-promised-but-never-delivered-p35pvvo6b) · XDA Developers · 0 upvotes · 0 comments - [I turned my phone into an AI agent powered by my local LLM, and it installed software on its own](https://daily.dev/posts/i-turned-my-phone-into-an-ai-agent-powered-by-my-local-llm-and-it-installed-software-on-its-own-dt5c9kqpw) · XDA Developers · 2 upvotes · 0 comments --- Tags: [#open-source](https://daily.dev/tags/open-source), [#android](https://daily.dev/tags/android), [#hardware](https://daily.dev/tags/hardware) [View this post on daily.dev](https://daily.dev/posts/i-built-riddleboox-an-ai-companion-that-writes-back-on-your-boox-awwtrx3mz) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"DiscussionForumPosting","mainEntityOfPage":"https://daily.dev/posts/i-built-riddleboox-an-ai-companion-that-writes-back-on-your-boox-awwtrx3mz","headline":"I built RiddleBoox: an AI companion that writes back on your BOOX","text":"RiddleBoox is a free, open-source native Android app for BOOX e-ink tablets that lets users write questions with a stylus and receive handwritten AI replies rendered back in ink. 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