Infrastructure
SMTP APIs
REST and SMTP submission APIs with per-stream credentials, envelope shaping, tagging, and webhook delivery events. Designed for application developers integrating outbound email into products.
Overview
The API sits in front of the same MTA infrastructure that serves our SMTP relay and dedicated deployments. It exists so that application developers can integrate outbound email without maintaining an SMTP client themselves.
Endpoints are versioned. Credentials are per stream. Webhook delivery is signed. All operations are idempotent by default.
Benefits
- One API for transactional and marketing streams
- Signed webhooks for delivery, bounce, complaint and open events
- Per-stream sending domains, tags and metadata
- Rate limits negotiated per client
Technical specifications
| Protocols | REST over HTTPS, SMTP submission |
|---|---|
| Auth | HMAC-signed API keys, IP allow-lists, mTLS on request |
| Webhooks | Signed, retried with exponential back-off |
Use cases
- — Product teams integrating notifications, receipts, magic links
- — Applications that require per-tenant sending attribution
Questions
Do you have SDKs?
The API is small enough that most clients integrate directly against HTTP. Reference clients for Node, Python and Go are available on request.
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