Sendmux vs T3 Code

Provision mailboxes on verified domains or a shared myagent.mx address, with clean JSON output that strips signatures and quotes.

Send over HTTP or SMTP using the same mailbox credential as a Bearer token and SMTP password, with Idempotency-Key retries and attachment support.

Bind keys to providers, delivery groups, weights, and quota windows so traffic stays inside the boundaries you set.

Signed webhooks for delivery and receipt events, an SSE stream for live mailbox clients, and typed change polling for resync.