Data Channels

Data channels allow you to send and receive arbitrary binary data between peers in a room. This is useful for implementing features like text chat, file sharing, game state synchronization, or real-time cursor positions.

Prerequisites

Before using data channels, you must be connected to a room. Data channels only work after you have successfully joined a room.

Channel Types

The SDK provides two types of data channels, each optimized for different use cases:

Reliable Channel

• Ordered delivery: Messages arrive in the order they were sent
• Guaranteed delivery: All messages will be delivered, with automatic retransmission if needed
• Use cases: Chat messages, file transfers, commands, or any data that must not be lost

Lossy Channel

• Unordered delivery: Messages may arrive out of order
• No retransmission: Messages may be dropped if the network is congested
• Lower latency: Faster delivery since there's no waiting for retransmissions
• Use cases: Real-time cursor positions, game state updates, live sensor data, or any data where the latest value matters more than every value

Broadcast Communication

Data channels work in a broadcast fashion - when you publish data, it is sent to all other peers in the room. Additionally:

• Messages sent on the reliable channel are only received by peers subscribed to the reliable channel
• Messages sent on the lossy channel are only received by peers subscribed to the lossy channel

This separation allows you to use both channels simultaneously for different purposes without interference.

Using Data Channels

Use the useDataChannel hook to work with data channels. The typical flow is:

1. Initialize the data channel after connecting to a room
2. Subscribe to incoming messages
3. Publish messages to other peers

For a complete step-by-step guide on implementing text chat, see Text Chat.