---
title: SMTP Relay Now Available for Telnyx Email API
canonical: https://telnyx.com/release-notes/email-smtp-relay
---
# SMTP Relay Now Available for Telnyx Email API

[Release notes](https://telnyx.com/release-notes)

# SMTP Relay Now Available for Email API

### 27, Oct 2026

Telnyx Email API customers can now send email over standard SMTP: point any existing mail system at `smtp.telnyx.com` and route email through Telnyx alongside API sends.

### What's new

* **Standard SMTP support:** Mail servers, frameworks, and legacy apps send through Telnyx with a host, port, and credential change. STARTTLS required, with `AUTH PLAIN` or `AUTH LOGIN` using your API v2 key.
* **One platform for API and SMTP:** SMTP submissions flow through the same pipeline as API sends: same verified domains, same quotas and billing, same detail records and webhooks.
* **Telnyx message ID in the `250` reply:** Correlation and support tooling work unchanged.
* **Messages up to 25 MB:** The relay advertises `SIZE 25000000` in EHLO and accepts messages up to that limit.
* **Wire-verified protocol contract:** Every reply string, timeout, and limit is published, including clean `552` rejections for oversized messages.
* **Provider migration guides:** Translation tables for 13 SMTP providers (SendGrid, Mailgun, SES, Postmark, and more), framework configurations, and a cut-over playbook.

### Why it matters

Most email infrastructure already speaks SMTP, which makes this the shortest path onto the platform. Apps that have sent mail for years can switch providers with a config change instead of a bespoke connector. And because SMTP rides the same pipeline as the API, one platform covers domains, quotas, billing, and events instead of stitching another vendor into the stack.

### Example use cases

* Teams running legacy applications and mail servers that can only send through SMTP.
* WordPress, Django, and Rails apps configured through framework mail settings.
* Organizations consolidating email with voice and messaging on Telnyx.

### Getting started

1. Point your mail system at `smtp.telnyx.com` on port 587 with STARTTLS enabled.
2. Authenticate with the username `apikey` and your Telnyx API v2 key as the password.
3. Send from a verified sending domain on your account.
4. Use the message ID from the `250` acceptance reply to match webhooks and Email Detail Records.

const nodemailer = require("nodemailer");

const transport = nodemailer.createTransport({
  host: "smtp.telnyx.com",
  port: 587,
  secure: false,     // 587 uses STARTTLS; 465 is not offered
  requireTLS: true,  // upgrade or abort
  auth: {
    user: "apikey",  // literal string
    pass: process.env.TELNYX_API_KEY,
  },
});

**Learn more** in the [SMTP Protocol Contract](https://developers.telnyx.com/docs/messaging/email/smtp-protocol-contract), the [SMTP Migration Guides](https://developers.telnyx.com/docs/messaging/email/smtp-migration-guides), and the [Send Email API reference](https://developers.telnyx.com/api-reference/email-messages/create-or-send-an-email-message).

[Start building](https://telnyx.com/sign-up)

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