Mailchimp SMTP (Mandrill) settings: smtp.mandrillapp.com, port 587
Mailchimp has no SMTP for marketing campaigns; its transactional add-on Mandrill does: host smtp.mandrillapp.com, ports 25/587/2525 STARTTLS or 465 SSL, username = your Mailchimp/Mandrill username, password = a Mandrill API key. Pricing and limits.
Mailchimp Transactional (Mandrill) outgoing mail server:
smtp.mandrillapp.com, port <code>587</code> (STARTTLS) or <code>2525</code> (STARTTLS) or <code>25</code> (STARTTLS) or <code>465</code> (SSL/TLS), username = your Mailchimp account username/email (any non-empty string is accepted; the key identifies you), password = a Mandrill API key from Mailchimp Transactional → Settings → SMTP & API Info.
Mailchimp Transactional (Mandrill) SMTP settings at a glance
| Outgoing (SMTP) host | smtp.mandrillapp.com |
|---|---|
| Ports & encryption |
587 — STARTTLS <em>(recommended)</em>2525 — STARTTLS25 — STARTTLS465 — SSL/TLS |
| Username | your Mailchimp account username/email (any non-empty string is accepted; the key identifies you) |
| Password | a Mandrill API key from Mailchimp Transactional → Settings → SMTP & API Info |
| Authentication | Mailchimp Transactional (Mandrill) is a paid add-on to a Mailchimp Standard plan or higher; the marketing product itself cannot be used as an SMTP server. |
How to set up Mailchimp Transactional (Mandrill) SMTP
- Enable Transactional Email in Mailchimp → Automations → Transactional Email; buy a block.
- Mandrill → Settings → SMTP & API Info → New API Key.
- App settings: host smtp.mandrillapp.com, port 587, STARTTLS, username = Mailchimp username, password = API key.
Sending limits
- Transactional blocks are bought in units of 25,000 emails (from about $20); no free tier beyond a small demo allowance.
- Sending domains must be verified with DKIM and SPF; the From domain must be verified.
Things that catch people out
- Marketing mail through Mandrill is against the terms and gets the account closed.
Common Mailchimp Transactional (Mandrill) SMTP errors
| Server reply | Meaning | Fix |
|---|---|---|
535 5.7.8 Authentication failed | Key invalid or Transactional not enabled. | Create a key in Mandrill after enabling Transactional. |
More codes: 535 authentication failed, 550 relay denied, 554 rejected as spam, connection timed out — or all SMTP error codes.
When Mailchimp Transactional (Mandrill) 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 Mailchimp Transactional (Mandrill) nowRelated settings
Mailchimp Transactional (Mandrill) SMTP — questions
Only via its transactional add-on Mandrill: smtp.mandrillapp.com on port 587 with STARTTLS, username = your Mailchimp username, password = a Mandrill API key. It is paid and transactional-only.
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