Session semantics

Understand how the Flutter SDK rotates sessions and how the engine stores the session handle for analysis and replay correlation.

Source of truthsdk/sankofa_flutter/lib/sankofa_flutter.dartserver/engine/cmd/sankofa/main.go

The Flutter SDK owns session lifecycle on the client side.

How session refresh works

Before a track call is recorded, the SDK:

loads the existing session ID
checks the last event timestamp
creates a new session when the timeout has elapsed
writes the updated timestamp back to storage

The session ID is injected into event properties as $session_id.

Why that matters

The engine promotes $session_id into a dedicated field. That makes session analysis useful for:

replay correlation
funnel debugging
investigation feeds
anomaly triage

Session ID is currently client-driven

The core engine does not create the session itself on v1 ingest. It promotes the session field when the client includes $session_id in event properties.

Default properties

See which contextual fields the engine promotes and why they matter for segmentation and analysis.

Analysis surfaces

See how the ingest model powers events, users, cohorts, insights, funnels, flows, retention, and replay.