bitchat README

The project's README from github.com/permissionlesstech/bitchat. As one markdown file: README.md.

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bitchat

A decentralized peer-to-peer messaging app with dual transport architecture: local Bluetooth mesh networks for offline communication and internet-based Nostr protocol for global reach. No accounts, no phone numbers, no central servers. It's the side-groupchat.

bitchat.free

📲 App Store

📲 Play Store

Getting a copy you can trust

Install from the App Store, or build from source you have verified. A compiled build from anywhere else cannot be verified — see Verifying bitchat for how to check source against the per-release hash manifest, and for what to do if that is the only build you can get.

This matters more than it usually would: this repository has been the target of takedown demands, and when a repository or releases page disappears, mirrors appear that nobody can check.

License

This project is released into the public domain. See the LICENSE file for details.

Features

Technical Architecture

BitChat uses a hybrid messaging architecture with two complementary transport layers:

Bluetooth Mesh Network (Offline)

Nostr Protocol (Internet)

BitChat's private-envelope format is proprietary and is not NIP-17, NIP-44, or NIP-59 compatible. It uses Nostr as a relay transport but only interoperates with BitChat clients: private payloads travel inside kind-1059 events whose v2:-prefixed content is a BitChat-specific XChaCha20-Poly1305 construction, not NIP-44 encryption.

Channel Types

mesh #bluetooth

Location Channels (block #dr5rsj7, neighborhood #dr5rs, country #dr)

Direct Message Routing

Private messages use intelligent transport selection:

  1. Bluetooth First (preferred when available)

    • Direct connection with established Noise session
    • Fastest and most private option

  2. Nostr Fallback (when Bluetooth unavailable)

    • Uses recipient's Nostr public key
    • BitChat's app-specific private-envelope encryption
    • Routes through global relay network

  3. Smart Queuing (when neither available)

    • Messages queued until transport becomes available
    • Automatic delivery when connection established

For detailed protocol documentation, see the Technical Whitepaper.

Setup

Option 1: Using Xcode

open bitchat.xcodeproj

For a signed device build, create your ignored local configuration and replace the example team ID with your Apple Developer Team ID:

cp Configs/Local.xcconfig.example Configs/Local.xcconfig

Local.xcconfig.example derives unique app and App Group identifiers from that team ID. The entitlement files already reference $(APP_GROUP_ID), so tracked project or entitlement files do not need to be edited.

Useful command-line checks from the repository root:

# macOS Debug build without signing
xcodebuild -project bitchat.xcodeproj -scheme "bitchat (macOS)" \
  -configuration Debug CODE_SIGNING_ALLOWED=NO build

# Full SwiftPM test suite
swift test

# iOS simulator tests
xcodebuild -project bitchat.xcodeproj -scheme "bitchat (iOS)" \
  -sdk iphonesimulator \
  -destination 'platform=iOS Simulator,name=iPhone 17' test

If iPhone 17 is unavailable, choose an installed simulator from:

xcodebuild -showdestinations -project bitchat.xcodeproj -scheme "bitchat (iOS)"

Option 2: Using just

brew install just
just check
just run

just build and just run use the current bitchat (macOS) scheme and keep Xcode output in the ignored .DerivedData/ directory. They never patch source, project, configuration, or entitlement files.

just clean removes only .DerivedData/ and .build/. It does not invoke Git or restore tracked files, so uncommitted work is preserved. just test runs the SwiftPM suite and just test-ios runs the iPhone 17 simulator suite.

Localization

bitchat (permissionlesstech/bitchat)

chat
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36.6K ·GitHub
Bitchat
What is this?BitChat is a decentralized peer-to-peer messaging app that uses Bluetooth mesh for offline, local chat and the Nostr protocol for internet-based global reach, with no accounts, phone numbers, or central servers.
Is this a chat app, or a protocol/library I build on top of?It's a finished native app for iOS and macOS, not a library or SDK — you install and run it directly, with IRC-style commands like /slap and /msg built in.
How do I get it running?Install from the App Store or Play Store, or build from source using Xcode with your own Apple Developer Team ID, or use the 'just' command runner (just build, just run) which wraps Xcode builds.
Can I trust any build I find online?No — only App Store builds or source you've personally verified against the release hash manifest are trustworthy, since the repo has faced takedown demands and unverifiable mirrors have appeared elsewhere.
Does it really work with no internet at all?Yes, the Bluetooth mesh transport works completely offline, routing messages peer-to-peer through nearby devices for up to 7 hops, making it usable in disasters or areas without connectivity.
Does the mesh network leave any trace of who I am?The app avoids accounts and phone numbers, but each device keeps a persistent identifier derived from its identity key, which a nearby radio could observe, and store-and-forward messages lack forward secrecy.
How does it decide whether to use Bluetooth or Nostr for a message?It prefers Bluetooth when a direct Noise-encrypted session is available (fastest and most private), falls back to Nostr using the recipient's public key when Bluetooth is unavailable, and queues messages for automatic delivery if neither transport is reachable.
What are the location-based channels?They are geographic chat rooms built on geohash coordinates over Nostr relays, with precision levels from city-block (#dr5rsj7) up to country/region (#dr), letting users join local or regional discussions without needing Bluetooth range.
Is BitChat's encryption compatible with other Nostr clients?No — BitChat's private-envelope format is proprietary, using a BitChat-specific XChaCha20-Poly1305 construction inside kind-1059 events rather than standard NIP-44 encryption, so it only interoperates with other BitChat clients even though it rides on Nostr relays.
What happens if I trigger the emergency wipe?A triple-tap instantly clears all local data from the device, useful for quickly protecting information in sensitive situations like protests.
What are similar projects?EnvoyMesh, nebula, tailscale, EasyTier, simplex-chat, ZeroTierOne, gun, Signal-iOS
Which topics is it in?nostr, bluetooth-le, mesh-network, bluetooth, decentralized, p2p, messaging, chat, encryption, swift, offline, mobile
Creator
permissionlesstech
Size
113.6 MB
Stars
36.6K
Updated
CommitSep 24Releasev1.7.1Jul 31
Age
1y
Commits · 90 Days