# Concept: Destination (connection)

A **destination** (a *connection* in the schema) is a pipe that receives every event a product synthesises. A product can have many; each delivers independently.

Supported destinations are Accoil, Segment, PostHog, Amplitude, Mixpanel, and any plain REST endpoint. Each carries a **write key** (a secret, stored encrypted and never shown back) and a small **configuration** (non-secret values like a base URL or region).

One config choice is set once and never changed: the **group identifier** — whether events group customers by `entitlement_number` or `entitlement_id`. Switching it later would re-key every group in the destination and fragment that pipe's analytics history, so the destination is effectively immutable: to change it you remove the connection and add a new one.

A destination can be **enabled** or **disabled**, and its full history can be **replayed** down the pipe on demand.

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