Updated 2026-10-08

How to Configure SMTP in listmonk

In listmonk, open Settings -> SMTP, set Host to smtp.bulko.io, Port to 587, Auth protocol to LOGIN, TLS to STARTTLS, enter your Bulko SMTP username and password, then click Test connection and Save. listmonk will send campaigns and transactional messages through that SMTP server.

Hostsmtp.bulko.io

Port587 · 465 · 2525

EncryptionSTARTTLS · SSL

Loginfrom dashboard

listmonk SMTP settings

Field	Value
Enabled	`On`
Host	`smtp.bulko.io`
Port	`587 (or 465 with TLS = SSL/TLS, or 2525 with STARTTLS)`
Auth protocol	`LOGIN (PLAIN also works)`
Username	`Your Bulko SMTP username (smtp_xxxxxxxxxxxxxxxx)`
Password	`Your Bulko SMTP password`
TLS	`STARTTLS for 587/2525, SSL/TLS for 465`
Skip TLS verification	`Off`
Max. connections	`A small number such as 5`
Default `from` email (Settings -> General)	`Your Name <[email protected]>`

Step-by-step setup

Buy an SMTP package on the Bulko SMTP Relay page and copy the username and password from Dashboard -> SMTP Access.
Log in to the listmonk admin and go to Settings -> General. Set Default `from` email to an address on a domain you control, for example Acme News <[email protected]>.
Open the SMTP tab. Edit the existing server block (or add a new one) and switch Enabled on.
Fill in Host smtp.bulko.io, Port 587, Auth protocol LOGIN, Username and Password, and set TLS to STARTTLS.
Leave Skip TLS verification off and set Max. connections to a modest value. Disable any other SMTP blocks you do not use, or listmonk will spread mail across them.
Click Test connection, enter a recipient in To e-mail and send. When the test succeeds, click Save.
Go to Settings -> Performance, turn on Enable sliding window limit and set Duration 24h and Max. messages 2000 to match Bulko's default daily limit (ask [email protected] for a higher limit).

listmonk settings to enter

# Values for listmonk: Settings -> SMTP
Enabled:               on
Host:                  smtp.bulko.io
Port:                  587
Auth protocol:         LOGIN
Username:              smtp_xxxxxxxxxxxxxxxx
Password:              YOUR_BULKO_SMTP_PASSWORD
TLS:                   STARTTLS
Skip TLS verification: off
Max. connections:      5

# Settings -> Performance (keep under the 2,000/day default limit)
Enable sliding window limit: on
Duration:                    24h
Max. messages:               2000

Send a test email

Use the Test connection button on the SMTP tab. listmonk asks for a To e-mail address (and, after a reload, to re-enter the password) and sends a message through the server. Success shows a confirmation and the email arrives in the inbox you entered.

Then create a small test list with your own addresses, send a campaign to it and confirm the campaign status reaches finished without errors in Logs.

Troubleshooting

Problem	Fix
Test connection hangs or times out	The server cannot reach the port. Some hosts block outbound SMTP. Try port 2525 with TLS set to STARTTLS, or ask your provider to open 587.
tls: first record does not look like a TLS handshake	TLS and port do not match. Use STARTTLS with 587 or 2525, and SSL/TLS only with 465.
535 Authentication failed	Check that Auth protocol is LOGIN or PLAIN, not None, and paste the username and password again from Dashboard -> SMTP Access. More on error 535: https://bulko.io/en/smtp-errors/535/.
Campaign pauses after many errors	listmonk stops a campaign when the Maximum error threshold is reached. Open Logs to see the SMTP replies. If you hit the daily limit, the sliding window limit in Settings -> Performance prevents this.
554 5.7.1 rejected	Bulko's content filter blocked the message for phishing, malware, impersonation or scam patterns. Review the template, links and From address.
Campaigns land in spam	Send from your own domain, verify it in Bulko for DKIM alignment, keep an unsubscribe link in every template, and check the domain with https://bulko.io/en/validators/blacklist-checker/.

FAQ

Can I use Bulko SMTP for listmonk newsletters?

Yes, for opt-in lists. Bulko allows opt-in newsletters and B2B outreach with an honest sender and opt-out. Purchased lists and personal addresses without consent are prohibited (see https://bulko.io/en/acceptable-use/).

How do I keep listmonk under the daily sending limit?

Turn on Enable sliding window limit in Settings -> Performance with Duration 24h and Max. messages 2000. listmonk then holds messages until the window clears instead of failing.

Which Auth protocol should I choose?

How much does it cost to send listmonk campaigns through Bulko?

Packages are one-time: $5 for 5,000 emails, $15 for 20,000, $30 for 50,000 or $60 for 150,000. There is no subscription and unused emails never expire.

Does Bulko handle bounces for listmonk?

Bulko's MTA handles delivery and bounce processing on its side. listmonk's own bounce processing needs a mailbox or webhook you configure separately, since Bulko SMTP has no inbox or IMAP.

Can I add several SMTP servers in listmonk?

Yes. listmonk supports multiple SMTP blocks and distributes mail across the enabled ones. Keep only the Bulko block enabled if you want all mail to go through it.

Get SMTP credentials for listmonk

One-time payment by card or crypto, no subscription. Unused emails never expire. 2,000 emails per day per SMTP account.

SMTP Relay 5K: $5 · 5000SMTP Relay 20K: $15 · 20000SMTP Relay 50K: $30 · 50000SMTP Relay 150K: $60 · 150000

See SMTP relay plans

What you can send: Acceptable Use Policy.