Why inbound Turns Email Into Agency Retainer Infrastructure

Inbound converts every address on a client domain into a structured JSON webhook, which means agencies can sell email automation as a managed service instead of a one-off integration. At $4/mo for 5,000 emails and $15/mo for 50,000 emails across 50 domains, the infrastructure cost is small enough to absorb into a retainer while the setup work stays billable. The catch is that Inbound requires developer implementation, so agencies without delivery capacity will struggle to resell it.