__event__ envelope with external_id, organization_id, application_id, and application_type fields so you can route events to the correct customer in your system.
To pre-filter delivery before events reach your endpoint, you can configure channels at creation time. Available filters include production, sandbox, Organization.<organization_id>, and Application.<application_id>. Filters can be combined.
Federation webhook endpoints can be created via the console under My Federation > Webhooks & Logs, or programmatically via POST /webhooks using your Federation API key.
For full implementation details, see the Organization Management guide.