BitChat vs Olvid

BitChat is a decentralized messaging app that uses Bluetooth mesh for nearby communication and Nostr relays for internet messaging. Bluetooth messages can pass between nearby devices across as many as seven hops without internet access. When Bluetooth is unavailable, the app can use Nostr; if neither route is available, messages can wait in a queue. Geographic chat rooms use geohash coordinates.

The app requires no account, phone number, or central server. Live mesh sessions use Noise XX for mutual authentication and forward secrecy, while private Nostr messages use an app-specific encrypted format that works only with BitChat clients. However, mesh announcements expose static keys and nicknames in cleartext, and a persistent per-device identifier can allow nearby listeners to follow a device over time and place. A triple-tap emergency wipe clears app data, including identity keys and queued messages. Android adds Wi-Fi Aware on supported devices and built-in Tor. BitChat is available for iOS, Android, and macOS, and is free.

Olvid is an instant messaging app for text messages and attachments, available on Android, iOS, Linux, macOS, web, and Windows. Olvid says it does not require identifying details such as a phone number, email, name, address, or birth date. It also says messages and metadata are end-to-end encrypted, so it cannot know who is communicating with whom. Each message and file uses a single-use ephemeral key, intended to protect message history if a key is compromised. The app supports synchronization across devices without a master device. Secure audio and video calls are end-to-end encrypted; video calls support up to two contacts, while group audio calls have no participant limit. Receiving calls is free, and initiating them is free during a one-month trial that ends without billing or automatic subscription. The free plan includes unlimited messages and attachments, group discussions, ephemeral messages, multiple profiles, and inbound calls. Business costs €990 a year; Enterprise costs €990.50 a year.