# Concept: Atlassian credential

An **Atlassian credential** is a developer space identity — the trio of **developer id** (from your Marketplace vendor URL), the **Atlassian email** that owns it, and an **API token** minted at id.atlassian.com. Products sync *as* one of these: the credential is what the sync presents to Atlassian's Marketplace reporting API, so it decides which apps' licences and transactions are visible.

The API token is **write-only**: stored encrypted, never echoed back — on an update, a blank token field means "keep the stored one". Deleting a credential is refused while any product still syncs as it; delete or re-point those products first.

One special case: a credential may carry a **mock base URL**. Products on it then sync from a mock Marketplace (fixture data through the identical client, auth, pagination and retry path) instead of Atlassian — that is how the demo runs offline.

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