Architecture

Truncus separates email delivery into two distinct layers.

Transport layer

Email transport is handled by AWS SES (eu-west-1) as primary, with Scaleway TEM (fr-par, France) as second provider; failover works where a domain is authenticated with both.

SES provides global deliverability infrastructure, established mailbox provider relationships, and bounce and complaint detection.

Truncus uses SES strictly as the transport layer. SES is not exposed in the API surface.

Control plane

The Truncus control plane runs in the EU: the API in Frankfurt (fra1), data in Supabase eu-central-1 (Frankfurt).

Responsibilities:

Deterministic delivery state resolution
Event storage (90-day retention)
Webhook dispatch and retry
Idempotency enforcement
Replay system
Suppression list management

Your API key, account data, delivery events, and webhook history are stored in the EU (Frankfurt). SES handles only the transport.

Delivery flow

API request received by control plane
Request validated (API key, payload, domain authorization)
Email submitted to transport layer (AWS SES eu-west-1 primary; failover to Scaleway TEM fr-par, France, where a domain is authenticated with both providers)
Terminal state resolved from SES feedback
Event stored in EU control plane
Webhook dispatched to your endpoint

Why this separation exists

Most email APIs expose transport acceptance as their delivery status. Acceptance means the receiving server agreed to process the message — not that it reached the inbox.

By maintaining a separate control plane on top of the transport layer, Truncus can:

Record each delivery outcome independently of transport
Store delivery data in the EU
Provide replay without re-sending
Enforce idempotency across retries

Data residency

Transport layer: AWS SES (eu-west-1) primary; Scaleway TEM (fr-par, France) second provider. Failover works where a domain is authenticated with both.

Control plane: EU (Frankfurt).

Account data, event logs, webhook history: EU.

Operated by Van Moose (Netherlands).