The control plane for multi-provider email delivery.
Cantalupe Sender receives transactional mail over standard SMTP and routes every recipient across MailBaby, Amazon SES and SendGrid with weighted balancing, automatic failover and precise per-recipient billing.
Built for reliable, accountable delivery.
Weighted round-robin routing
Distribute each recipient across MailBaby, Amazon SES and SendGrid using smooth weighted round-robin — deterministic and auditable, never random.
Automatic failover
Temporary provider errors before acceptance re-route to the next provider. Once a message is accepted, it is never sent twice.
Per-recipient accounting
Every recipient is one billable unit, written to an idempotent ledger so retries and failover can never double-count.
Tenant isolation
Row-level security scopes every customer to their own domains, credentials, messages and usage. Admins see the whole platform.
SMTP-compatible ingest
Your WordPress, WooCommerce, ERP or CRM keeps talking plain SMTP. The gateway authenticates and hands off to the routing plane.
Full event timeline
Trace every recipient from received to routed, accepted and delivered — with provider attribution and bounce reasons.