Email — HTTP API vs SMTP relay

Start here: E-mail — documentation hub.

Routee Transactional Email supports two send paths. Both use the same Connect Application Id and Application Secret, write to the same delivery logs, and require a verified domain and authorized sender.

Comparison

	HTTP API	SMTP relay
Best for	Modern apps, microservices, serverless, JSON-native stacks	Existing MTAs, CMS plugins (WordPress, Laravel), legacy mail configs
Connect to	`POST https://connect.routee.net/transactional-email`	`smtp10.amdtelecom.net`
Auth per request	OAuth Bearer token (`scope=transactional_email`)	SMTP AUTH — Application Id = username, Application Secret = password
Message format	JSON (`html`, `text`, attachments, headers)	Standard MIME (RFC 5322)
Immediate response	HTTP 200 + `trackingId`	SMTP `250` acceptance
Callbacks on send	`callback.statusCallback`, `callback.eventCallback` (HTTP API only)	Not configured in MIME — use tracking API or portal logs
Scheduling / TTL	`scheduledDate`, `ttl`, `maxAttempts` in JSON body	Depends on client; Routee accepts standard SMTP submission
Billing flag	`isSingleChannel: true` required on every HTTP send	N/A (account resolved at SMTP auth)

When to choose HTTP

You already use Connect OAuth for SMS, Viber, or other Routee APIs.
You want structured JSON, attachments as base64, custom headers, and DSN options in one request.
You need delivery or open/click webhooks configured at send time.
You run serverless or API-first backends without an outbound SMTP client.

Guide: Transactional Email API v2 — overview

When to choose SMTP

You already have Postfix, Exim, Sendmail, or a CMS mail plugin configured for SMTP relay.
You migrate from another ESP without rewriting the send layer.
Your ops team standardizes on port 25/587 relay rather than REST.

Guide: Transactional Email — SMTP relay

TLS summary (SMTP only)

Port	Mode
25	Plain connect → STARTTLS → AUTH
587	Implicit TLS (SSL from first byte) → AUTH — do not use STARTTLS on cleartext 587

Tracking (both paths)

Action	HTTP API
Search logs	`POST /email/tracking`
Full timeline	`GET /email/tracking/single/{trackingId}`
Portal	Email → Logs on go.routee.net

Allow 1–2 minutes after send before log rows appear.

Guide: Email tracking, statuses & callbacks

Prerequisites (both paths)

Complete before first send — see Domain & authorized senders:

Active transactional email subscription
Verified sending domain (SPF + DKIM)
Authorized sender for your From address
Connect application with transactional_email scope

E-mail
Email resources overview
Send your first transactional email (tutorial)
Send transactional email via SMTP (tutorial)