Email Delivery Control Plane

Your product email shouldn’t depend on a black box.

Sendarix is the control plane for multi-tenant SaaS email. Route by tenant, domain, message type and live relay health. Isolate blast radius. Recover from deliverability incidents before your users notice — on infrastructure Sendarix operates end to end.

No credit card · Drop-in SMTP & API · Sendarix-managed delivery infrastructure

sendarix · control plane · live routing
EU deferrals rising — OTP stream rerouted → US pool
Your SaaS API · SMTP SENDARIX route · isolate monitor · recover policy engine EU pool US pool Dedicated

Representative product UI — illustrative data, not live customer metrics.

The multi-tenant problem

One tenant can break email for everyone.

In a shared sending setup, a single abusive tenant, misconfigured domain, or relay incident can damage reputation across your entire customer base. Black-box senders show you the symptoms — not the controls to contain them.

Shared reputation pool

no control plane
t01
t02
t03
t04
t05
t06
t07
t08

One abusive tenant poisons the pool — every customer degrades.

Isolated with Sendarix

blast radius contained
t01
t02
t03
t04
t05
t06
t07
t08

The bad tenant is quarantined to its own pool — everyone else stays healthy.

See the isolation model

Built-in delivery, not a passthrough

Sendarix runs the delivery layer.

Messages leave through Sendarix-operated relay pools and IP infrastructure — not a third-party ESP hidden behind your API. Define how every message is routed, isolated, monitored and recovered inside one control plane you operate.

architecture · native delivery stack
Your application SENDARIX CONTROL PLANE Routing policy + failover Isolation tenant + pool Monitor events + health Recover reroute EU relay US relay Dedicated IPs Tenant pools Inbox providers · Gmail · Microsoft 365 · Yahoo

Representative product UI — illustrative data, not live customer metrics.

Inside the control plane

This is the operator view.

The same dark operator console your team works in every day — routing rules, tenant isolation, live events and relay health in one place.

routing · rule builder
WHEN message_type = otp AND route_health(eu_pool) < 95%
ROUTE → us-relay POOL transactional-critical
ELSE → eu-relay POOL shared-default
rule active · evaluated per message

Representative product UI — illustrative data, not live customer metrics.

isolation · tenants
TenantPoolSignalStatus
acme-corpdedicated-ip-12Clean sendshealthy
northwindshared-eu-3Stablehealthy
tenant_8842quarantine-1Complaints risingisolated
globexshared-us-1Stablehealthy

Representative product UI — illustrative data, not live customer metrics.

events · message lifecycle · msg_01HF2K…
03:14:02 accepted api · idempotency_key=otp_8842
03:14:02 queued pool=transactional-critical
03:14:03 sent relay=eu-primary
03:14:051 deferred 421 throttled · eu-primary
03:14:06 rerouted policy=failover → us-relay
03:14:07 delivered inbox

Representative product UI — illustrative data, not live customer metrics.

deliverability · relay health · 24h
Relay pathSignalStatus
EU transactionalStable deliveryhealthy
US bulkLow deferralshealthy
Dedicated tenantElevated deferralsdegraded

Representative product UI — illustrative data, not live customer metrics.

webhooks · delivery + retries
200 OKmessage.deliveredattempt 1/8
503message.bouncedretry in 30s · backoff
200 OKmessage.bouncedattempt 2/8
signaturet=1718…,v1=4f3a…verified

Representative product UI — illustrative data, not live customer metrics.

Operator views below use representative UI with illustrative data — not live customer metrics.

An incident, narrated

A relay path degrades. Your users never notice.

At 03:14 the EU transactional pool starts throttling OTPs. Sendarix detects the deferral, reroutes the stream to a healthy US relay, and delivery recovers automatically — no engineer paged, no firefighting.

events · message lifecycle · msg_01HF2K…
03:14:02 accepted api · idempotency_key=otp_8842
03:14:02 queued pool=transactional-critical
03:14:03 sent relay=eu-primary
03:14:051 deferred 421 throttled · eu-primary
03:14:06 rerouted policy=failover → us-relay
03:14:07 delivered inbox

Representative product UI — illustrative data, not live customer metrics.

cURL Node SMTP
# Send a critical email through a routing policy
curl -sS -X POST 'https://app.sendarix.com/v1/email/send' \
  -H 'Content-Type: application/json' \
  -H 'X-API-Key: YOUR_API_KEY' \
  -H 'Idempotency-Key: otp_8842' \
  -d '{"to":"user@acme.com","template":"password_reset","routing_policy":"transactional-critical"}'
const sendarix = require("sendarix")(process.env.SENDARIX_KEY);

await sendarix.email.send({
  to: "user@acme.com",
  template: "password_reset",
  routingPolicy: "transactional-critical",
  idempotencyKey: "otp_8842"
});
# Drop-in SMTP — keep your integration, gain a control plane
host:     smtp.sendarix.com
port:     587  (STARTTLS)
username: "your_sending_key"
header:   X-Sendarix-Policy: transactional-critical

Built for engineers

Ship in one request. Keep your SMTP.

Drop-in SMTP and a REST API with idempotency keys and routing policies as first-class fields. Migrate one critical stream first — leave everything else where it is.

Why switch

Own the delivery layer. Operate it like infrastructure.

Sendarix combines a control plane with the relay infrastructure behind it — policy-first routing, multi-tenant isolation, and automatic recovery you can actually operate.

Sending → Infrastructure control → Classic ESPs Legacy relay Sendarix

Built like infrastructure

Isolation, signing and governance by default.

Security headers, signed webhooks, SSO, DPA and tenant isolation are part of the architecture — not an upsell.

TransportTLS + STARTTLS
WebhooksSigned + retried
AuthSSO / SAML
LegalDPA · AUP · Privacy
IsolationPer-tenant pools

Capabilities listed above reflect platform design — not live system status or third-party certifications.

Security & compliance

Pricing

Priced by the control you need.

Start free and grow into routing, isolation and governance as your infrastructure matures — not just by email volume.

Free

Test the integration

Starter

Production transactional

Professional

Routing + failover

Business

Tenant isolation + SSO

Enterprise

Dedicated infra + SLA

See full pricing

Protect critical email across every tenant.

Move your most critical stream to Sendarix this week. Keep everything else exactly where it is.