Email infrastructure for AI agents
Sendmux is an email API designed specifically for AI agents and applications that need to send, receive, and manage email programmatically. It combines agent inboxes, outbound sending, routing, delivery events, and provider integrations in one platform. Its focus on structured email data makes it particularly useful for developers building automated email workflows.
Smarter sending and receiving
One of Sendmux’s strongest features is its agent-shaped inboxes, which return cleaned, structured JSON instead of forcing AI systems to process lengthy HTML emails. Signatures and quoted history can be removed by default, helping reduce unnecessary processing. This platform also supports HTTP, SMTP, SDKs, CLI, MCP, and integrations with AI frameworks.
For outbound email, users can connect providers such as Gmail, SendGrid, Mailgun, Resend, Microsoft 365, or Amazon SES. Weighted routing, quotas, and automatic failover provide additional control over delivery. A potential con is that this is primarily developer-focused, so users without API or infrastructure experience may find the setup and configuration more technical than traditional email platforms.
A promising agent-first solution
Overall, Sendmux offers a focused approach to email infrastructure for AI-powered applications. Its combination of dedicated inboxes, structured message parsing, provider flexibility, routing, and real-time events makes it compelling for developers building autonomous agents. With a free tier offering two mailboxes, it is also relatively easy to test before scaling.
