What are the best practices for migrating ESPs with subdomain and IP warmups?

Email marketer from GMass advises using consistent subdomains for different types of emails (e.g., transactional vs. marketing) to ensure a stable reputation for each. Clearly separate the two to protect your transactional emails.

Email marketer from Mailjet recommends using subdomains to segment your email traffic and protect your main domain's reputation. Warming up subdomains separately allows you to isolate any deliverability issues and maintain a consistent sending reputation for important transactional emails.

Email marketer from EmailGeeks Forum suggests to start your IP warmup with your most engaged subscribers who are most likely to open and click on your emails. Sending to these recipients will quickly establish a positive sending reputation with ISPs.

Email marketer from Talos Intelligence emphasizes the need to check the reputation of your sending domain and IP address using tools like Talos Intelligence. A poor reputation can significantly impact your deliverability.

Email marketer from GlockApps states that before starting your IP warmup, thoroughly test your email infrastructure to ensure that your authentication records are properly configured and that your emails are not being flagged as spam. Use tools like GlockApps to check your inbox placement rates.

Email marketer from Reddit suggests to gradually increase your sending volume over several weeks, starting with small batches and slowly ramping up as your reputation improves. Avoid sending large volumes of email all at once, as this can trigger spam filters.

Email marketer from Litmus indicates that engaging recipients with high-quality, relevant content is crucial during the warmup phase. Focus on providing value to your subscribers and encourage them to interact with your emails.

Email marketer from MailerQ suggests setting up feedback loops with major ISPs to receive notifications when subscribers mark your emails as spam. This allows you to quickly identify and address any issues that may be affecting your deliverability.

Email marketer from ZeroBounce explains cleaning your email list before starting your IP and subdomain warmup. Removing inactive or invalid email addresses will improve your engagement rates and protect your sender reputation.

Marketer from Email Geeks explains that preserving the exact FQDN isn't as important as preserving the 5321.From domain itself. All of these things are data points with reputation systems and they are all factors in identifying a mail flow and attributing it a reputation, they suggest focusing on a smooth cut-over and updating authentication.

Marketer from Email Geeks explains that whether a single dedicated IP is enough depends on the reputation and whether you're getting throttled or not. They suggest starting with 1 and seeing how things go, and then add another if you need to later.

Expert from Email Geeks explains that if you’re doing ANY overlap in ESPs at all, then you’re going to want to set up a new subdomain.

Expert from Spam Resource explains that proactive reputation management is crucial during ESP migration, including monitoring blacklists, setting up feedback loops, and addressing any deliverability issues promptly to minimize disruptions and maintain a positive sending reputation.

Expert from Email Geeks explains that the reverse DNS of the IP address and the hostname the client uses in the HELO don't matter much at all, as long as they're syntactically valid and don't look like consumer malware infested cable modems.

Expert from Email Geeks explains that you can customize the hostnames to match your brand but you're going to have to do a warmup process.

Expert from Email Geeks confirms that splitting marketing messages from transactional seems like a safe thing to do still, and that it’s the standard recommendation.

Expert from Word to the Wise recommends engaging with ISPs during the migration and warmup process. This involves communicating your plans, addressing any concerns they may have, and building a collaborative relationship to ensure smooth deliverability.

Expert from Email Geeks explains that what you really _don't_ want to do is have your mailgun setup steal sendgrid hostnames.

Expert from Email Geeks explains that at a lot of consumer domains IP doesn’t win. IP gets you in through the SMTP transaction and then is basically irrelevant for delivery (ie, if the mail was accepted, the IP has a base reputation)

Expert from Email Geeks explains you’ll have to warm up the new IP / domain combination whether you stay or change.

Documentation from Amazon Web Services explains that warming up IP addresses involves gradually increasing the volume of email sent from new IP addresses to establish a positive sending reputation with ISPs. This helps avoid being flagged as spam and ensures better deliverability.

Documentation from Google Postmaster Tools explains the need to leverage Google Postmaster Tools to monitor your domain's reputation and identify any potential deliverability problems. This tool provides valuable insights into how Google views your sending practices.

Documentation from Sendgrid emphasizes the importance of setting up proper email authentication (SPF, DKIM, DMARC) before starting your IP and domain warmup. This helps prove that you are a legitimate sender and improves your chances of reaching the inbox.

Documentation from RFC Editor (RFC 5321) explains that adhering to SMTP standards for email transmission is critical for deliverability. Ensuring proper formatting and protocol compliance can help avoid being flagged as spam.

Documentation from Microsoft SNDS explains the need to use Microsoft's Smart Network Data Services (SNDS) to monitor your IP address's reputation and identify any potential issues with Microsoft's email services. This tool provides valuable insights into how Microsoft views your sending practices.

Documentation from SparkPost recommends actively monitoring your deliverability metrics, such as bounce rates, complaint rates, and inbox placement rates. This will help you identify any issues early on and make necessary adjustments to your warmup strategy.