Sendmux
Email Inbox API + Sending for AI Agents
...It gives every agent a real email identity: a dedicated mailbox that can receive inbound email, read threads, process attachments, use cleaned message content, send replies, and react to new messages through signed webhooks or Server-Sent Events.
For outbound email, Sendmux lets teams send through Gmail OAuth, Outlook OAuth, customer-owned SMTP providers, or managed Amazon SES. Delivery groups support weighted routing, sender-domain routing, per-provider quotas from per second to per day, health checks, and failover, so teams can keep control of sending instead of relying on one provider.
Sendmux also includes tenant isolation, team and mailbox-scoped API keys, OpenAPI docs, SDKs for TypeScript, Python, Go, PHP, and Ruby, the sendmux CLI, and MCP tools for AI agents. ...