appData (21)

The appData message is the primary means of transporting data for an active Mini-App session. It is a generic container sent repeatedly between two peers after a session has been established via appRequest and appRequestAccept.

For example, a real-time game would use a continuous stream of appData messages to send player coordinates back and forth.

Core Data Types

• IxiBytes: See IxiBytes Encoding.

Payload Structure

The payload is an AppDataMessage object, which encapsulates the session ID and the raw application data.

Field	Data Type	Min	Max	Description
sessionId	IxiBytes	*	*	The unique identifier of the active Mini-App session this data belongs to.
data	IxiBytes	1	*	The raw, application-specific payload for this message.

Behavioral Notes

• Prerequisite: This message is only valid within an active session. A node should ignore appData messages with a sessionId that does not correspond to an established session.
• Unreliable by Default: The StreamMessage envelope for appData typically sets requireRcvConfirmation to false. This is suitable for applications that prioritize low latency over guaranteed delivery, such as streaming media or real-time games, which have their own methods for handling packet loss.
• Context: The meaning of the data field is defined entirely by the Mini-App itself. The S2 protocol treats it as an opaque byte array.