Jack Dorsey, co-founder of Twitter and Square, has introduced a new messaging app called Bitchat. Unlike most modern apps, Bitchat doesn’t need the internet, cell service or even a user account to function. Instead, it uses Bluetooth and a system called mesh networking to send messages between nearby devices.
The app is currently available in beta on TestFlight and Dorsey has published a white paper on GitHub for those interested in the technical details. He described the project as a personal experiment involving “Bluetooth mesh networks, relays and message encryption.”
Bitchat allows people to send encrypted messages directly from phone to phone using Bluetooth. As users move through physical space, their devices can form small local networks. Messages hop from one device to another, eventually reaching people who may be outside the normal Bluetooth range. No internet, no servers, just nearby phones passing messages quietly along.
Messages disappear after a short time and are stored only on the user’s device. There is no central server involved, which means no data is collected and nothing is stored in the cloud. The design reflects Dorsey’s ongoing interest in privacy, decentralization and user-owned technology.
Bitchat also offers group chats called “rooms.” These can be named with hashtags and protected by passwords. The app includes a “store and forward” feature as well, if someone is offline, messages can be saved and delivered later when they reconnect to the mesh network. A future update is expected to add support for WiFi Direct, which will improve speed and extend range.
The app’s design is similar to Bluetooth tools used during protests in Hong Kong in 2019. In those situations, decentralized apps allowed people to communicate securely without relying on the internet, which was often blocked or monitored.
While Bitchat may sound experimental, its goals are clear: to give users a private, censorship-resistant way to communicate, even in places where traditional networks are unavailable or untrustworthy.
Whether Bitchat becomes widely used remains to be seen. But in a world increasingly concerned with privacy, surveillance and digital independence, Dorsey’s latest project may offer a small but meaningful alternative to the centralized platforms we rely on every day.
So what does this mean in practice?
Bitchat operates on Bluetooth Low Energy (BLE) to create a decentralized “mesh” network. Each phone using the app connects to nearby devices and relays messages across the network, allowing communication beyond typical Bluetooth range.
This system means that: no internet or cell signal is required, no accounts or phone numbers are needed, messages are private, encrypted and temporary
When users open the app: their device advertises itself via Bluetooth, it detects other Bitchat users nearby, messages are relayed through multiple devices until they reach the intended recipient. If someone is offline, the system stores the message temporarily and delivers it once they reconnect. Group chats are organized through “channels,” which can be public or password-protected.
Though fully functional offline, Bitchat will eventually offer an optional connection to the internet using the decentralized Nostr protocol. This feature will allow users to sync selected messages or channels across regions without compromising privacy.
Importantly, this is opt-in only and users remain in full control of what is shared online.
Bitchat is free to use, modify and share. It’s released into the public domain, meaning there are no licenses, fees or restrictions. It’s as much a tool for individuals as it is a reference for developers, humanitarian workers or privacy advocates building offline communication systems.
Bitchat operates over Bluetooth Low Energy (BLE) mesh networks, so its range and connectivity depend on physical proximity and environmental factors:~10 to 30 meters (≈30 to 100 feet) in open or semi-open environments, shorter (5–15 meters) indoors or with walls/obstacles. It can theoretically span hundreds of meters or more, depending on number of active users, their physical distribution, whether there are relay “bridge” nodes in overlapping zones
When groups of users are within overlapping range, bridge nodes relay messages between clusters. This allows messages to “leapfrog” across neighborhoods, events or buildings, as long as each hop stays within BLE range. The more people running Bitchat in an area, even passively, the farther and more reliably messages can travel.
How messages reach their destination without phone numbers
Bitchat does not use phone numbers, emails or permanent identifiers. Instead, it relies on cryptographic public keys and ephemeral peer IDs to securely identify devices during a session.
Each user generates a public/private key pair when the app starts. The public key serves as a temporary “address” or identity. The private key is used to decrypt incoming messages and sign outgoing ones. This key pair only lives as long as the session, no long-term tracking.
When sending a message, the message is encrypted using the recipient’s public key. It includes the recipient’s peer ID (derived from the public key) and a unique message ID. Only the device with the matching private key can decrypt it.
As the message travels across the mesh, each device checks the recipient ID in the message. If the recipient ID matches its own, it accepts and decrypts the message. If not, it relays the message to nearby peers, unless the message’s TTL (Time to Live) has expired.
Each message has a unique message ID and devices maintain a short-term cache to prevent duplicate forwarding, loops in the mesh and wasting bandwidth or battery.
What is NOSTR and why it matters
Nostr stands for “Notes and Other Stuff Transmitted by Relays.” It’s an open protocol (not an app or company) for building decentralized social networks. Nostr is a grassroots, open-source effort. But it has gained attention from some big names such as Jack Dorsey who donated Bitcoin to developers building on Nostr. Several crypto and privacy communities are actively contributing to it.
Nostr is a new way to build social apps, open, decentralized, and controlled by users, not companies. Instead of one big company controlling everything (like Twitter or Facebook), Nostr uses many independent relays (servers) to pass messages around.
If one relay bans you, you can use another, or run your own. There are already Nostr-based apps for chatting, tweeting, blogging, and more.
Nostr is known for censorship resistance, simplicity and ownership. No company or government can shut down the whole network. The protocol is intentionally very basic, dumb relays and smart clients. You control your identity, your content, and your audience.
