ZappMessaging - P2P Messaging SDK

Open-source peer-to-peer messaging SDK for Zapp applications, built on the Holepunch/Pear stack (Hyperswarm + Bare).

Overview

ZappMessaging provides a comprehensive P2P messaging solution with no central server:

• Direct Messages: Private peer-to-peer conversations addressed by public key, with no accept step in the SDK
• Group Chats: Multi-person chats with invite system and permissions
• Media Transfer: Chunked image and GIF transfer with content-addressed storage
• No Accounts: Peer discovery over the Hyperswarm DHT with Noise-encrypted transport
• Privacy-First: Keypair-based identity, no phone numbers or tracking
• Resilient Delivery: An optional blind peer mirrors encrypted cores and relays connections, so chat keeps working behind restrictive networks without seeing message contents

Packages

• core/ - Platform-agnostic JavaScript modules (CommonJS, Bare runtime)
• ios/ - Swift framework for iOS apps with XCFramework
• android/ - Kotlin library for Android apps with AAR
• server/ - Blind-peer relay and invite mailbox for offline delivery

Quick Start (iOS)

import ZappMessaging

let sdk = ZappMessagingSDK(
    config: ZappMessagingConfig(dataDir: appSupportDirectory)
)

try await sdk.initialize()

// Chat identity is derived from the host wallet's BIP39 seed.
let identity = try await sdk.restoreFromSeedPhrase(seedPhrase, displayName: "Alice")
print("Chat public key: \(identity.publicKey)")

let conversation = try await sdk.createConversation(
    type: .direct,
    participants: [recipientPublicKey],
    displayName: "Bob"
)

let message = try await sdk.sendMessage(
    conversationId: conversation.id,
    content: "Hello!"
)
print("Sent \(message.id)")

See ios/README.md for setup, configuration, and the full Swift surface.

Chat Types Supported

Direct Messages

• Discovery: Order-independent topic derived from both public keys
• Use Case: Private conversations, direct deals, customer support
• Access: An inbound invite auto-joins the pairwise topic, replies with the reciprocal core key, and then raises conversation.invite_received. Accept and block policy is the host application's responsibility

Group Chats

• Discovery: Random group ID with invite system
• Use Case: Trading groups, project teams, private communities
• Access: Invite-based with member management and permissions

Architecture

┌─────────────────┐    ┌──────────────────┐    ┌─────────────────┐
│   iOS/Android   │    │  Native Wrapper  │    │  JS Worklet     │
│   App           │◄──►│  (Public API)    │◄──►│ (Core Logic)    │
└─────────────────┘    └──────────────────┘    └─────────────────┘
                                                       │
                                              ┌─────────────────┐
                                              │  Hyperswarm     │
                                              │  (P2P Network)  │
                                              └─────────────────┘

Documentation

• Core API Reference - IPC protocol between the native wrappers and the worklet
• iOS SDK - Swift setup and usage
• Android SDK - Kotlin setup and usage
• Server - Blind-peer relay and invite mailbox deployment

Technology Stack

Core P2P Infrastructure

• P2P Runtime: BareKit worklet (JavaScript in Bare kernel)
• Networking: Hyperswarm (DHT-based peer discovery with Noise protocol)
• Crypto: Hypercore-Crypto (Ed25519 keypairs, Blake2b hashing)
• Storage: Corestore (RocksDB-backed atomic storage)
• Offline Delivery: Blind-peer mirroring via blind-peering and protomux-rpc
• Compatibility: B4A (Buffer/Uint8Array cross-platform)

Mobile Integration

• iOS: BareKit XCFramework with Swift Package Manager
• Android: BareKit AAR with Gradle support
• IPC: NDJSON (newline-delimited JSON) over BareKit IPC
• Architecture: Single JavaScript core with platform-native wrappers

Contributing

See CONTRIBUTING.md for development setup, commit message and pull request expectations, and the Developer's Certificate of Origin sign-off.

Security

Report vulnerabilities through the private security advisory flow. Do not file them as public issues.

License

Apache License 2.0 - see LICENSE file for details.

Related Projects

• JustZappIt - Landing site
• zapp-android - Android app