MailerSend SMTP settings: smtp.mailersend.net, port 587

MailerSend SMTP relay: host smtp.mailersend.net, port 587 STARTTLS or 465 SSL, an SMTP user generated per domain in the MailerSend dashboard. Free tier and setup steps.

MailerSend outgoing mail server: smtp.mailersend.net, port <code>587</code> (STARTTLS) or <code>465</code> (SSL/TLS) or <code>2525</code> (STARTTLS), username = the SMTP username generated under Domains → your domain → SMTP, password = the generated SMTP password.

MailerSend SMTP settings at a glance

Outgoing (SMTP) hostsmtp.mailersend.net
Ports & encryption
587 — STARTTLS <em>(recommended)</em>
465 — SSL/TLS
2525 — STARTTLS
Usernamethe SMTP username generated under Domains → your domain → SMTP
Passwordthe generated SMTP password
AuthenticationSMTP users are per verified domain; the From address must belong to that domain.

How to set up MailerSend SMTP

  1. Domains → Add domain → add DNS records → verify.
  2. Domain → SMTP → Generate new user.
  3. App settings: host smtp.mailersend.net, port 587, STARTTLS, username/password = generated SMTP user.

Sending limits

  • A small free tier (a few hundred to a few thousand emails per month depending on current plans) requires account approval; paid plans from about $28/month.
  • Domain verification with SPF, DKIM and Return-Path CNAME required.

Things that catch people out

  • New accounts are in "trial" with limited recipients until approved.

Common MailerSend SMTP errors

Server replyMeaningFix
535 Authentication failedDashboard credentials used.Generate an SMTP user for the domain.

More codes: 535 authentication failed, 550 relay denied, 554 rejected as spam, connection timed out — or all SMTP error codes.

When MailerSend is not enough for your app

When a provider caps you or blocks a port, point the same app at QueenSMTP instead: host smtp.queensmtp.com, port 587 (STARTTLS) or 465 (SSL), your SMTP username and password from the dashboard. $5/year plus $0.10 per 1,000 emails, 100 free a day to test.

Get SMTP credentials — free to test Test MailerSend now

Verified 2026-08-30 against MailerSend's documentation and live DNS. Found a change? Tell us.

MailerSend SMTP — questions

smtp.mailersend.net on port 587 (STARTTLS) or 465 (SSL), with an SMTP user generated for your verified domain.