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How Switching ESPs Impacts your Deliverability
How Switching ESPs Impacts your Deliverability

Ensure a smooth switch to SmartrMail

Written by Peter Connolly
Updated over a week ago

Switching from an ESP to another will have an impact on your deliverability, no matter which ESP you’re switch from/to.

When moving to a new ESP your entire sending reputation doesn’t make the move with you. 

As a sender your sending reputation is tied to:

  • Your sending IP address, which is directly linked to your ESP (this can’t be migrated)

  • Your sending domain, such as

Over time ISPs such as Gmail and Outlook have learnt that your emails come from a combination of these elements and if you kept up with deliverability best practices would have sent your emails to the inbox.  Changing any of these elements causes highly sophisticated algorithms to kick of a review process to evaluate your sending reputation before deciding where to send your emails to the inbox or the spam folder.The more of theses elements you change, the more ISPs are likely to reevaluate your sending reputation from scratches.

You might be thinking that switching ESPs isn’t worth the risk, but if you’re sending emails people want to receive you don’t need to worry. If you follow a few steps a switch can have a positive impact on your deliverability.

Here are a few things you can do to make sure your switch to SmartrMail improves your email deliverability:

  • Use the same “from” email address. Keeping this element constant will help ISPs validate that you’re the one sending your emails. 

  • Send from the same domain you were using previously (optional). If you had DKIM and SPF records set up to send off your own domain with your last ESP, you want to change those settings to send with SmartrMail. You only need to do this if you have more than 20,000 subscribers. Reach out via the in-app chat and we’ll send you instructions on how to do this.

  • Remove your unsubscribes. Unsubscribes and invalid emails marked in your old ESP might not have been recorded in your e-commerce platform, and may have been imported into SmartrMail. Export your list and remove them before sending any emails. Read: Bulk Unsubscribing Customers.

  • Clean your subscribers list. If you’re already doing the work moving over to a new ESP, it’s the perfect time to clean your list. There’s no point in moving over subscribers who haven’t opened your emails in months. We strongly recommend that you clean subscribers off your list that haven’t opened any of your emails in the last 6months. Here’s how to do it with MailChimp:

  • Don’t add more inactive subscribers to your list. This may seem obvious but some senders find it tempting to now add a huge list of inactive email addresses that they haven’t been sending to. You’re likely in a review period during your switch so if you’re thinking of adding any inactive subscribers that you weren’t sending to before – just don’t do it!

If your open rates and deliverability still aren’t what you expect, don’t worry. It usually takes 3-4 emails for ISPs to finish their review process and for your deliverability to return to normal. Make sure you’ve followed all the steps above and send us a message via the in-app chat if you have any questions.

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