Zencargo Webhooks
Outbound HTTP webhooks. Zencargo POSTs a JSON payload (topic, targetType, targetId) to a customer-registered HTTPS callback URL when events such as BOOKING_CREATED occur, signed with a base64 Zencargo-Hmac-SHA256 header for verification. This is server-to-endpoint HTTP push, not a WebSocket or GraphQL subscription. Subscriptions are configured in the Zencargo app, not via the API.