# Concept: Licence

A **licence** is one customer's entitlement to a Marketplace app — their tier, hosting (cloud or server/data-center), status (active, cancelled, …), trial flag, ARR, partner, and maintenance window. It is keyed by an **entitlement number**, which is the natural key the sync reconciles against.

Each sync fetches the current licences from Atlassian and **upserts** them: `first_seen_at` is preserved, `last_seen_at` advances, and the diff between the previous snapshot and the new one is what the synthesiser turns into lifecycle events (trial started, converted, renewed, churned, …).

So a licence row is a *current profile*, not a history — the history lives in the events synthesised from how that profile changed over time.

Related: [Sync run](/concepts/sync_run) · [Product](/concepts/product)