Send email with the SMTP relay

The SMTP relay lets any software that can send email over SMTP deliver through InboxRoads: order confirmations, password resets, contact-form notifications and newsletters to people who signed up. Each recipient uses 1 credit from your normal balance.

Before you start

1. Verify a sending domain. Go to Sending domains, add your domain and publish the DNS records. The relay only accepts mail whose From address uses one of your verified domains. See Add and verify a sending domain.
2. Request access. Open SMTP & API in the menu, fill in your website, expected volume and what you will send, and submit. Every account is reviewed; you get an email when access is active.

Create SMTP credentials

1. Go to SMTP & API.
2. Under SMTP credentials, enter a name (for example WooCommerce store) and click Create.
3. Copy the username and password straight away. The password is shown only once. If you lose it, create a new credential and revoke the old one.

Create one credential per website or app, so you can revoke one without affecting the others.

Connection settings

Examples

WordPress (with any SMTP plugin, such as WP Mail SMTP or FluentSMTP): choose Other SMTP, enter the host, port 587, encryption TLS, turn authentication on, and paste the username and password. Set the From email to an address on your verified domain.

Laravel (.env):

MAIL_MAILER=smtp
MAIL_HOST=smtp.inboxroads.com
MAIL_PORT=587
MAIL_USERNAME=ir-xxxxxxxxxxxx
MAIL_PASSWORD=your-smtp-password
MAIL_FROM_ADDRESS=orders@yourdomain.com

Node.js (Nodemailer): host: "smtp.inboxroads.com", port: 587, secure: false, auth: { user, pass }. Nodemailer upgrades the connection with STARTTLS automatically.

Limits

• Up to the number of recipients per message shown on your SMTP & API page (50 by default).
• Maximum message size shown on the same page (20 MB by default, including attachments).
• A daily sending limit per account. When you reach it, the server answers with a temporary 451 error and well-behaved apps retry later. Contact us to raise your limit as your volume grows.

What happens after sending

Each accepted message gets an ID (for example 250 2.0.0 OK queued as 01J…) and appears in the Message log with the status of every recipient. Recipients who hard-bounced or complained before are skipped and not charged, and emails that fail permanently are refunded. See also Relay webhooks.

Common errors