About this app
OpenBook Chat is a communication platform built for people who value privacy and live beyond borders. Encrypted messaging, real-time translation in 30 languages, an AI companion, and powerful productivity tools — all in one app. COMMUNICATE WITHOUT LIMITS Enable OpenBook Zero for messages only you and your recipient can read — end-to-end encryption with X25519 key exchange and per-message ephemeral keypairs. Once it's on, nobody, not even us, can access your encrypted conversations. BREAK THE LANGUAGE BARRIER Chat in any language with real-time auto-translation across 30 languages. Powered by on-device Apple Translation for privacy, with AI fallback for broader coverage. LUNA — YOUR AI COMPANION Luna is OpenBook's built-in AI companion. Ask questions, get things done, translate on the fly, and have real conversations — all without leaving the app. CIRCLES — EPHEMERAL GROUP MOMENTS Create a Circle for a trip, a project, a moment. It sunsets automatically. No archive anxiety, no thread management. AMBIENT MUSIC ROOMS Over 450 original AI-generated tracks across 14 themed rooms. Find your focus, wherever you are. DOCUMENT SIGNING Sign PDFs, add annotations and stamps, all without leaving OpenBook. Upgrade to OpenBook Pro for expanded access to Luna and AI-powered features. OpenBook. Simply beyond chat. Terms of Use: https://moneta8.com/terms.html Privacy Policy: https://moneta8.com/privacy.html
Audience growth
Ratings growth
Baseline captured. Growth appears after the crawler observes a changed rating count.
Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.
Price tracking
Price intelligence
First snapshot captured. The trend line starts after the next crawler price observation.
- First observed Sep 8, 2026 · 3:59 AM Free
Screenshots
