So I built AgentMailr. You call an API to create an inbox, your agent gets a unique email address, and replies route back to that specific agent. Works for both inbound (OTP parsing, reply routing) and outbound (cold email, notifications).
Bring your own domain is supported so emails come from your domain, not ours. REST API and MCP server are live. Node/Python SDKs are in progress.
Happy to answer questions about the architecture or how I'm handling multi-agent routing.