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How to change sending domain with list of 80K

  • December 16, 2025
  • 6 replies
  • 93 views
E
Contributor I
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Hi,

Our client is considering a rebrand, which will naturally involve changing the sender domain.

I have been unable to find a clear, practical guide outlining how to do this step by step, or the recommended process for making the change safely. My main concern is that there does not appear to be an option to add and warm up a new sender domain alongside the existing one. As a result, I would really appreciate guidance on the exact steps involved.

I have previously worked with a competing EMS that supports multiple sender domains, which makes this process very straightforward. In this case, however, I am a bit unsure of the best approach, so any advice or direction would be greatly appreciated.

Thank you in advance.

Best answer by talha.hussain

Hi ​@eugene_odr, this is a very valid concern and you are right to be cautious here.

Klaviyo currently supports only one active branded sending domain per account, which means you cannot run the old and new sender domains in parallel for a true side by side warmup like some other ESPs allow. Because of that, changing domains needs to be handled carefully, especially with a list of 80k.

Here is the safest and most commonly used approach.

Step 1. Set up and authenticate the new sending domain
Before switching anything, fully configure the new domain in Klaviyo and complete DNS authentication (SPF, DKIM, tracking domain). Do not send from it yet.

Step 2. Pause or significantly reduce volume
When you switch the sending domain, inbox providers treat it as a brand new sender. Even though your IP reputation remains, domain reputation does not carry over. Plan to reduce volume and frequency immediately after the switch.

Step 3. Warm the new domain gradually
Start by sending to your most engaged recipients only, for example people who have opened or clicked in the last 30 days. Send small volumes at first and increase gradually over 2 to 3 weeks. Avoid blasting the full 80k list early.

Step 4. Expand engagement windows slowly
Once performance stabilizes, expand to 60 day and then 90 day engaged segments. Monitor spam complaints, bounces, and open rates closely throughout this process.

Step 5. Resume normal cadence
After a successful warmup period and stable metrics, you can return to normal sending volume and cadence.

 

    6 replies

    talha.hussain
    Problem Solver IV
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    • talha.hussain
    • Problem Solver IV
    • Answer
    • December 17, 2025

    Hi ​@eugene_odr, this is a very valid concern and you are right to be cautious here.

    Klaviyo currently supports only one active branded sending domain per account, which means you cannot run the old and new sender domains in parallel for a true side by side warmup like some other ESPs allow. Because of that, changing domains needs to be handled carefully, especially with a list of 80k.

    Here is the safest and most commonly used approach.

    Step 1. Set up and authenticate the new sending domain
    Before switching anything, fully configure the new domain in Klaviyo and complete DNS authentication (SPF, DKIM, tracking domain). Do not send from it yet.

    Step 2. Pause or significantly reduce volume
    When you switch the sending domain, inbox providers treat it as a brand new sender. Even though your IP reputation remains, domain reputation does not carry over. Plan to reduce volume and frequency immediately after the switch.

    Step 3. Warm the new domain gradually
    Start by sending to your most engaged recipients only, for example people who have opened or clicked in the last 30 days. Send small volumes at first and increase gradually over 2 to 3 weeks. Avoid blasting the full 80k list early.

    Step 4. Expand engagement windows slowly
    Once performance stabilizes, expand to 60 day and then 90 day engaged segments. Monitor spam complaints, bounces, and open rates closely throughout this process.

    Step 5. Resume normal cadence
    After a successful warmup period and stable metrics, you can return to normal sending volume and cadence.

     

    Talha Hussain - Senior Email Marketing Spacilest
    Byrne C
    Community Manager
    Forum|alt.badge.img+28
    • Byrne C
    • Community Manager
    • December 18, 2025

    Hi ​@eugene_odr,

    Believe it or not, as long as you’ve been sending emails from the same root domain for at least 30 days, you actually won’t need to warm a new sending domain. For example, if your website is klaviyo.com, and you were previously using send.klaviyo.com as your branded sending domain, but you change it to email.klaviyo.com, you won’t need to warm that new branded sending domain. This is referenced in our Understanding which warming process to use article.

    Has your website itself been the same for at least 30 days? Have you been sending emails from an address that matches your website for that amount of time? If so, you can feel safe switching to the new branded sending domain, and sending as normal!

    E
    Contributor I
    Forum|alt.badge.img
    • eugene_odr
    • Author
    • Contributor I
    • December 20, 2025

    Hi ​@eugene_odr,

    Believe it or not, as long as you’ve been sending emails from the same root domain for at least 30 days, you actually won’t need to warm a new sending domain. For example, if your website is klaviyo.com, and you were previously using send.klaviyo.com as your branded sending domain, but you change it to email.klaviyo.com, you won’t need to warm that new branded sending domain. This is referenced in our Understanding which warming process to use article.

    Has your website itself been the same for at least 30 days? Have you been sending emails from an address that matches your website for that amount of time? If so, you can feel safe switching to the new branded sending domain, and sending as normal!

    Hi, thank you for your answer. We have been sending emails for a very long time from the original domain, but as mentioned in my original post, client is rebranding, which involves the name change, which in turn means changing the URL and, of course, the sending domain. 
    I don’t think it’s a good practice to send emails from info@newbusinessaddress.com when your sending domain would be mail.oldbusinessaddress.com, and point all the traffic to newbusinessaddress.com 
    Or am I missing something?

    E
    Contributor I
    Forum|alt.badge.img
    • eugene_odr
    • Author
    • Contributor I
    • December 20, 2025

    Hi ​@eugene_odr, this is a very valid concern and you are right to be cautious here.

    Klaviyo currently supports only one active branded sending domain per account, which means you cannot run the old and new sender domains in parallel for a true side by side warmup like some other ESPs allow. Because of that, changing domains needs to be handled carefully, especially with a list of 80k.

    Here is the safest and most commonly used approach.

    Step 1. Set up and authenticate the new sending domain
    Before switching anything, fully configure the new domain in Klaviyo and complete DNS authentication (SPF, DKIM, tracking domain). Do not send from it yet.

    Step 2. Pause or significantly reduce volume
    When you switch the sending domain, inbox providers treat it as a brand new sender. Even though your IP reputation remains, domain reputation does not carry over. Plan to reduce volume and frequency immediately after the switch.

    Step 3. Warm the new domain gradually
    Start by sending to your most engaged recipients only, for example people who have opened or clicked in the last 30 days. Send small volumes at first and increase gradually over 2 to 3 weeks. Avoid blasting the full 80k list early.

    Step 4. Expand engagement windows slowly
    Once performance stabilizes, expand to 60 day and then 90 day engaged segments. Monitor spam complaints, bounces, and open rates closely throughout this process.

    Step 5. Resume normal cadence
    After a successful warmup period and stable metrics, you can return to normal sending volume and cadence.

     

    Thank you! I think this is the way we will have to proceed. 
    Of course, this means reduced email activity for at least 30 – 60 days. 
    So the sequence of the the whole process would be:
    1) Disable all email automations. 
    2) Change the domain, authenticate, link it with the google postmaster
    3) Gradually enable automations, but limit to people who are most engaged
    4) Reintroduce campaigns and ramp up quantities as per your guideance. 

     

    larawoodward
    Problem Solver I
    Forum|alt.badge.img
    • larawoodward
    • Problem Solver I
    • December 22, 2025

    This is a valid concern, Klaviyo doesn’t support warming a new sending domain in parallel, so the safest approach is to authenticate the new domain early, then switch and warm it gradually by sending first to your most engaged subscribers only. Avoid blasting the full 80k right away, keep content and cadence consistent, and pause low-engagement segments until reputation builds. Many teams also pre-announce the rebrand so the new sender domain doesn’t feel unfamiliar to inbox providers or subscribers.

    Byrne C
    Community Manager
    Forum|alt.badge.img+28
    • Byrne C
    • Community Manager
    • December 22, 2025

    ​@eugene_odr,

    Thanks for clarifying! Since your rebrand involves changing your website domain entirely, then yes, I can confirm that you would need to warm your new sending domain. Apologies for the miscommunication!

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