Hey there,
Thanks for the question, these are distinct event types:
Activity: Represents a completed workout session with a defined start and end time (e.g., user starts a run, finishes it). Sent once when the workout ends, identified by a unique summary_id.
Daily: Represents a cumulative summary of ALL activity for a 24-hour period. It's sent multiple times throughout the day as the user moves around -- each payload is an updated total up to that point. You should always overwrite the previous daily data for a given date with the latest one (identified by start_time + end_time).
They don't exactly duplicate each other, daily includes general movement/steps/calories throughout the day, while Activity is specifically about discrete workout sessions. A user who goes for a run would generate both: one Activity event for the run, and updated Daily events reflecting the run's contribution to their overall daily totals.
Docs: https://docs.tryterra.co/docs/event-types