Updated 2026-10-08
How to Send Email From Zapier Through Your Own SMTP Server
Use the SMTP by Zapier app: in a Zap, add the Send Email action, connect a new account with Host smtp.bulko.io, your Bulko username and password, Use TLS set to Yes and Port 587, and set From Email to an address on your domain. Do not pick port 465, because Zapier does not support implicit SMTPS on it.
Zapier SMTP settings
| Field | Value |
|---|---|
| Host | smtp.bulko.io |
| Username | Your Bulko username, for example smtp_xxxxxxxxxxxxxxxx |
| Password | Your Bulko SMTP password from Dashboard > SMTP Access |
| Use TLS | Yes |
| Port | 587 (2525 if 587 fails; not 465) |
| From Email (connection) | Optional, an address on your domain if the connection test fails |
| From Email (action) | An address on a domain you control, for example [email protected] |
| From Name (action) | Your company or product name |
Step-by-step setup
- Buy an SMTP package on the Bulko SMTP Relay page. Your username and password are shown in Dashboard > SMTP Access and emailed after payment.
- In Zapier, create or open a Zap, add an action step and search for SMTP by Zapier. Choose the Send Email action event. This is a different app from Email by Zapier, which sends from Zapier's own servers with tight limits.
- Under Account, click Sign in to add a new SMTP connection.
- In the connection window, enter Host
smtp.bulko.io, Username and Password from your Bulko dashboard, set Use TLS to Yes and choose Port587. Zapier upgrades the connection with STARTTLS on this port. - Leave the connection's From Email field empty at first. If Zapier reports a connection problem, fill it with an address on your domain and try again. Confirm the window to save the account.
- Configure the action: From Name, From Email (required, on your own domain), Reply To, To (required), optional Cc and Bcc, Subject (required) and Body (required, plain text). Add HTML Body for a formatted version; Zapier still needs the plain-text Body as a fallback. Map data from the trigger step into any of these fields.
- Optional: verify your domain in Sending Domains and publish the DKIM TXT record (selector
bk1) and thebnc.yourdomain.comCNAME so SPF, DKIM and DMARC align.
With SMTP by Zapier, Zapier only talks to your mail server; the relay does the actual delivery. That is why the 5 per day and 10 per hour caps of Email by Zapier do not apply here, and why delivery details live in your relay account rather than in Zapier.
Send a test email
In the action's Test section, click Test step. Zapier sends a real email using the values you mapped, so set To to an inbox you can read first. A successful test returns a result with the message details, and the email arrives within a minute or two. If the test fails, Zapier shows the SMTP error returned by the server: compare it with the table below. Open the received email, view the original headers and check that SPF and DKIM pass, then publish the Zap.
Troubleshooting
| Problem | Fix |
|---|---|
| Connection fails or hangs on port 465 | Zapier does not support SMTPS (implicit TLS) on port 465, which is what Bulko runs on 465. Switch Port to 587 with Use TLS set to Yes. |
| Timeout or connection refused on 587 | Try Port 2525 with Use TLS set to Yes; Bulko runs STARTTLS on 2525. Port 25 is not offered for submission. |
| 535 Authentication failed | Reconnect the account and paste the Username and Password again from Dashboard > SMTP Access. The username looks like smtp_xxxxxxxxxxxxxxxx, not an email address. More causes: bulko.io/en/smtp-errors/535/. |
| Connection test fails although credentials are right | Fill in the optional From Email field in the connection with an address on your domain and reconnect. |
| 554 5.7.1 message rejected | Bulko's content filter blocked the message as phishing, malware, impersonation or a scam. Check the mapped Subject, Body and links coming from the trigger. |
| Emails go to spam | Use a From Email on your own domain, verify it in Sending Domains and check SPF with the Bulko SPF checker. Always fill in the plain-text Body next to HTML Body. |
FAQ
What is the difference between Email by Zapier and SMTP by Zapier?
Email by Zapier sends from Zapier's servers and is capped at 5 emails per day on Free plans and 10 per hour on paid plans. SMTP by Zapier connects to your own SMTP server, which then sends the mail under your domain.
Which port works with SMTP by Zapier?
Port 587 with Use TLS set to Yes. Port 2525 with TLS is a fallback. Port 465 does not work with Bulko because Zapier does not support implicit SMTPS.
Is there a sending limit with SMTP by Zapier and Bulko?
Bulko allows 2,000 emails per day per SMTP account by default, and [email protected] can raise it. Each sent email also counts as a task in your Zapier plan.
Can Zapier read replies through Bulko?
No. Bulko is outgoing only, without IMAP. Set Reply To to a mailbox you already use and connect that mailbox to Zapier if you need to process replies.
How much does it cost?
Bulko SMTP is pay-as-you-go: $5 for 5,000 emails, $15 for 20,000, $30 for 50,000 or $60 for 150,000, one-time payment and unused emails never expire.
Get SMTP credentials for Zapier
One-time payment by card or crypto, no subscription. Unused emails never expire. 2,000 emails per day per SMTP account.
What you can send: Acceptable Use Policy.