Overview
Switching from one email service provider (ESP) to another affects your deliverability — no matter which ESP you're switching from or to. Your sending reputation doesn't move with you automatically.
Your sending reputation is tied to three things:
Your sending IP address, which is linked directly to your ESP. This resets when you switch, since you're moving to a new (usually shared) sending IP.
Your sending domain (e.g.
yourstore.com). Domain reputation is portable — it follows your domain across ESP switches rather than resetting from scratch, and it's now the dominant signal inbox providers use to decide where your email lands.Your from email address
Inbox providers like Gmail, Outlook, and Yahoo build trust in these elements together over time. Since your domain reputation carries over, keeping the same domain (ideally one that's already authenticated) is one of the best things you can do to keep your deliverability steady through a switch.
Note: switching ESPs isn't inherently risky. If you're sending emails people actually want, and you follow the steps below, a switch can even improve your deliverability.
How to make your switch to SmartrMail go smoothly
Keep the same "from" email address. This helps inbox providers recognize you're still the same sender.
Set up domain authentication. Since February 2024, Gmail and Yahoo require full authentication (SPF, DKIM, and DMARC records) for any sender exceeding 5,000 emails a day — and SmartrMail recommends setting this up regardless of your volume, since it significantly improves deliverability and protects your brand from spoofing. If you had DKIM/SPF set up with your previous ESP, you'll need to set up the equivalent through SmartrMail instead. This is now fully self-service: follow our Custom Sending Domain setup guide, which includes an automated setup tool as well as manual steps for Shopify-managed domains and other DNS providers.
Remove your unsubscribes before sending. Unsubscribes and invalid emails from your old ESP may not have been recorded by your e-commerce platform, and could get re-imported into SmartrMail. Export your list and remove them first — see our guide on bulk unsubscribing contacts.
Clean your list while you're at it. If you're already moving to a new ESP, it's a good time to clean house — there's no benefit to bringing over subscribers who haven't engaged in a long time. Rather than a flat time cutoff, use SmartrMail's segment tools to identify unengaged subscribers directly — for example, subscribers who haven't opened or clicked in a while (see our domain warming guide for the same segment approach used there). If you're coming from Mailchimp, their guide on removing inactive subscribers can help you identify who to leave behind before importing.
Don't add previously-inactive subscribers during your switch. You're likely in a review period — adding a large batch of subscribers you weren't already sending to can work against you.
Important: if your deliverability dips after a switch, expect recovery to take a few weeks of consistent, gradual sending — not just a handful of emails. This matches the same timeline as our domain warming guide. Make sure you've followed the steps above, and contact us via in-app chat if it's taking longer than expected.
FAQs
Does switching ESPs wipe out my sending reputation completely?
Not entirely. Your domain reputation — which is now the most important signal inbox providers use — actually follows your domain across ESP switches rather than resetting. What does reset is your IP reputation, since a new ESP means a new sending IP. Keeping the same, already-authenticated domain is one of the best ways to preserve your deliverability through a switch.
Will switching to SmartrMail hurt my deliverability?
Not necessarily. Any ESP switch triggers a review period with inbox providers, but if you follow the steps above, your deliverability can recover quickly — or even improve.
How long does the review period usually take?
Expect a few weeks of consistent sending for deliverability to fully normalize, rather than just a handful of emails — this matches current industry understanding of how domain and IP reputation actually recover. If your open rates haven't improved after following the steps above and giving it some time, reach out via in-app chat.
Do I need to set up a custom sending domain when switching to SmartrMail?
Yes — SmartrMail recommends this for everyone, regardless of sending volume, since it improves deliverability and protects your brand from spoofing. See our Custom Sending Domain setup guide for the self-service setup process.