How to switch email marketing platforms without ruining deliverability

Maybe it's the rising costs. Perhaps it's the cluttered dashboard, the lack of responsive support, or the realisation you're paying for features you never touch.

Whatever your reason for switching email marketing platforms, the honest truth is that the move will affect your deliverability in the short term. A temporary dip in open rates is normal - and manageable - but only if you approach the switch thoughtfully.

How does changing email platforms affect deliverability?

When you move to a new email marketing platform, you can't take all of the sending reputation you've built up with your old platform. That's because your reputation is tied to three things:

• Your sending IP address - provided by your email marketing platform, so it stays behind when you leave.
• Your sending domain - typically the same as your website domain (e.g. yourbusiness.com).
• Your 'from' email address - the specific address you send from, e.g. contact@yourbusiness.[com].

You can carry over the reputation built on your sending domain and 'from' address, provided you don't change either when you move. But because your IP address will change, inbox providers like Gmail, Outlook, and Yahoo will detect this and begin re-evaluating your sender reputation - and during that review period, they tend to be cautious. Your first few campaigns from the new platform may be more likely to land in spam, which can cause a temporary dip in open and click rates.

The good news? There are concrete steps you can take to minimise this impact.

4 steps to take before leaving your current email platform

The goal is to arrive at your new platform with the cleanest, most engaged list possible. Here's what to do while you're still on your old platform.

Step 1: Identify your most engaged subscribers

This group of contacts will be your greatest asset in the early days with your new platform. In your current tool, create a segment of subscribers who have both opened and clicked your recent campaigns - these are your most active contacts.

Mark them clearly so you know who to email first after you've made the move (more on this below).

If your list is larger than 30,000 subscribers, it's worth segmenting more granularly:

• Most active - engaged with all of your last six campaigns
• Active - engaged with any of your last six campaigns
• Inactive - not engaged with any of your last six campaigns
• New subscribers - received fewer than six campaigns so far

Before you make the move, aim to shift as many inactive subscribers as possible into the active group using a re-engagement campaign.

Step 2: Run a re-engagement campaign

While still on your old platform, identify subscribers who haven't opened or clicked a recent campaign. What counts as 'recent' depends on your sending frequency - for weekly senders, the last six campaigns are a reasonable window; for monthly senders, the last three.

Send this inactive segment a direct email asking whether they still want to hear from you. Those who engage by opening and clicking the CTA confirm their interest. Those who don't engage at all should be manually unsubscribed before you migrate.

This might feel counterintuitive - few marketers enjoy shrinking their list - but it pays off. A smaller, engaged list is far more valuable to your deliverability than a large, unresponsive one. It will also reduce your costs on your new platform, since most tools price based on subscriber count.

📝 For a full walkthrough, see our step-by-step re-engagement campaign guide.

Step 3: Identify and remove recurring soft bounces

Some platforms automatically unsubscribe contacts after a certain number of consecutive soft bounces. Many don't. Check your current platform's policy - if it handles this automatically, skip ahead to step 4.

If not, here's how to do it manually:

1. Decide how many consecutive soft bounces should trigger an unsubscribe (we suggest six, adjusted for your sending frequency)
2. Export bounce reports from that many recent campaigns
3. In a spreadsheet, merge the reports and identify contacts appearing across all of them - these are your persistent soft bouncers
4. Mark them as unsubscribed and re-import them so they no longer receive campaigns

A note on hard bounces…

Most platforms automatically remove hard bounces, but check yours does. If not, unsubscribe all hard bounces manually before migrating.

For a refresher on the difference: soft bounces are temporary delivery failures (e.g. a full inbox); hard bounces are permanent (e.g. the email address no longer exists). Both types damage your sender reputation when left unchecked, but hard bounces are the more serious issue.

Step 4: Export detailed list data from your current platform

Export your list with full engagement data - ideally with segments already labelled as most active, active, inactive, and unsubscribed. This data will be essential for protecting your deliverability in the early stages on your new platform.

While you're at it, note down your current campaign performance benchmarks (open rates, click rates, bounce rates). For the fairest comparison later, look back to your earliest campaigns on this platform too - that's when you were building your reputation on a new IP, which mirrors the position you'll be in when you switch.

6 steps to take when joining your new email platform

Step 1: Verify your domain (including DMARC)

When you join a new email marketing platform, your sending address is usually verified as part of sign-up. But for the best deliverability, go further: verify your sending domain fully, including SPF, DKIM, and DMARC records.

• SPF tells inbox providers that your new platform's servers are authorised to send on your behalf.
• DKIM adds a digital signature that proves the email hasn't been tampered with in transit. Together, these protect your sender reputation from day one.
• DMARC is increasingly non-negotiable. Since February 2024, both Google and Yahoo have required bulk senders to have a DMARC record in place. Microsoft followed suit in May 2025. Non-compliant emails now risk temporary delays or permanent rejection by Gmail alone.

Use the same domain you were verified on with your old platform, so you carry over as much of the reputation you've built as possible.

📝 Here's how to verify your domain with EmailOctopus

Step 2: Import your list with all the data

Import your contact list in full, maintaining all the engagement segments and statuses you exported. In particular:

• Import active and most active subscribers, with custom fields marking their engagement level.
• Import unsubscribed contacts separately - most platforms will require you to do this with a different status - or leave them out entirely.
• Double-check that no previously unsubscribed contacts are accidentally imported as subscribed.

Getting this right matters both for deliverability and legal compliance. Emailing contacts who have previously opted out risks spam complaints and could violate GDPR, CAN-SPAM, or other applicable regulations.

📝 Here's how to import contacts into EmailOctopus

Step 3: Keep your 'from' email address the same

Your IP address is going to change - that's unavoidable. But your sending domain and 'from' email address don't have to. Keep both the same as your old platform, and you limit the number of changes inbox providers need to assess.

Any unnecessary changes at this stage give inbox providers more to scrutinise and can slow down the process of re-establishing your reputation. Keep things consistent while your sender reputation rebuilds on the new IP.

Step 4: Send to your most active subscribers first

Resist the temptation to send your first campaign to your entire list. Instead, start with your most active subscribers - the ones who reliably open and click.

High engagement on your first sends tells inbox providers that you're a trustworthy sender operating from a new IP address. It's the single most effective thing you can do to get your reputation off to a strong start.

You might use this first email to let your most engaged readers know you've switched platforms, and ask them to add you to their safe senders list as a precaution. Once this initial campaign has gone out, you can resume sending to your full list as normal.*

*This assumes you're moving to a shared IP address. If you're moving to a dedicated IP, you'll need to follow a structured IP warm-up process. EmailOctopus does not currently offer dedicated IP addresses.

Step 5: Maintain your existing sending patterns

Inbox providers notice sudden changes in behaviour - a sharp increase in sending frequency, or a long silence followed by a bulk send, are both red flags. Maintain the same cadence you had with your old platform.

This is also a good moment to use segmentation if you haven't been doing so already - targeted campaigns to engaged sub-groups will keep engagement rates high and your sender reputation healthy during the transition period.

Step 6: Allow time for your reputation to settle

Expect the first 30–45 days with your new platform to feel like a recalibration period. Inbox providers take roughly this amount of time to adjust to your new sending setup, and some short-term variability in open rates is normal.

During this period, monitor your bounce rates and spam complaints closely. Work with your new platform's support team if you notice anything concerning. Welcome emails are a great way to boost engagement from the moment new subscribers join, which feeds positively into your reputation during this window.

By the end of those six weeks, if you've followed these steps alongside good sending practices, your deliverability and engagement metrics should be back to where they were - or better.

Who needs to follow all of these steps?

Not everyone needs to follow every step to the letter. Here's a rough guide:

• Large, established lists (30,000+ subscribers, long sending history): Follow all of these steps carefully. You have the most to protect and the most to gain from a thorough approach.
• Smaller or newer lists: You may find a full re-engagement campaign less necessary and can likely move more quickly to sending to your whole list. Focus on steps 5–10 at a minimum.
• Struggling with low engagement already: Use the switch as a genuine reset. Clean your list, tighten up your segments, and treat this as an opportunity to build better habits from scratch.

Ready to make the switch?

Switching email marketing platforms doesn't have to be disruptive. Most senders who follow this process see their deliverability recover within four to six weeks - often ending up in a stronger position than before, because the migration forced a useful list clean-up.

If you're thinking of switching to EmailOctopus, our support team is on hand to walk you through the process and give personalised guidance at every step.