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Switching SMTP providers can affect deliverability if domain authentication and IP reputation are not handled carefully. This guide walks you through a safe cutover so your messages keep landing in the inbox.

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Before you start

  • Keep your old provider active until cutover is complete and stable. Removing it too early can leave you without a working sending path.
  • If you use a dedicated IP with mySMTP (the default plan), plan to warm it up gradually. Sending full volume from a cold IP can trigger blocks.
  • If you use a shared IP plan (DK only), you can send at normal volume once DNS is verified.

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Migration checklist

1

Sign up and get credentials

Create your account at clients.mysmtp.com, complete activation, and note your SMTP hostname, username, and password from the setup email. See Sign up and activate your account and Setting up SMTP credentials.
2

Add SPF and DKIM for mySMTP

Add include:spf1.mysmtp.com to your domain SPF record. A new record looks like v=spf1 include:spf1.mysmtp.com ~all; during migration, keep the old provider’s include in the same record. Add mySMTP DKIM TXT/CNAME records as shown in your dashboard or setup email. Keep your old provider’s records in place for now. See DNS setup for authentication.
3

Set up your application

Update the SMTP hostname, port, and credentials in your apps, CMS, or code. Use the hostname from your setup email (for example relayxx.mysmtp.com) on port 587 with STARTTLS. See Supported SMTP ports and encryption.
4

Warm up your dedicated IP gradually

Start with a small daily volume and increase slowly over days or weeks. This builds sender reputation on your new IP. See Warm up plans and use the warm-up generator in the mySMTP Deliverability Toolbox.
5

Monitor bounces, complaints, and delivery

Watch your sending dashboard and inbox placement during the transition. Use the Sender Readiness Checklist and Email Header Analyzer in the mySMTP Deliverability Toolbox to verify authentication and headers.
6

Remove old provider DNS records last

Only after sending is stable and reputation metrics look good, remove the old provider’s SPF include and DKIM CNAME/TXT records. Updating DNS too early can break authentication if you need to roll back.
Use the free mySMTP Deliverability Toolbox with 19 tools including SPF Validator, One-Click SPF/DKIM/DMARC Checker, and Email Header Analyzer.

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Provider-specific migration guides

SendGrid

Move from SendGrid SMTP to mySMTP. Update hostname, credentials, and SPF/DKIM records.

Mailgun

Move from Mailgun SMTP to mySMTP. Update hostname, credentials, and SPF/DKIM records.

Amazon SES

Move from Amazon SES SMTP to mySMTP. Update hostname, credentials, and SPF/DKIM records.

Brevo

Move from Brevo SMTP to mySMTP. Update hostname, credentials, and SPF/DKIM records.

Postmark

Move from Postmark SMTP to mySMTP. Update hostname, credentials, and SPF/DKIM records.