With the recent growth SendGrid has seen in our customer base, the Delivery Consulting team has loved the growing opportunity to work closely with so many great new or established companies. It has been a valuable experience for both parties.

Senders who make a choice to use any Email Service Provider (ESP), such as SendGrid, are always looking for good email delivery. They want the email sent out on a daily/weekly/monthly basis to get out the door successfully and reach the intended recipients.

This success largely involves making sure the sender is following email best practices. However, even if you already are following best practices, there are additional considerations when switching ESPs.

What is your reputation as a sender?

Your reputation will depend on the following areas:

  • Open Rate: When a recipient opens your message and the images are loaded
  • Click Rate: When a recipient engages with a link in your message
  • Bounce/Block Rate: How many messages don’t get delivered compared to what you tried to deliver
  • Complaint Rate: Of all of your recipients who received your messages, how many of them marked your messages as “spam” or “junk”
  • Unsubscribe Rate: How many senders are choosing to unsubscribe from your messages compared to how many are receiving them

We want to remind senders that all of the metrics mentioned above (as well as many others that are only monitored or available to the ISPs such as Gmail/Yahoo) will affect each sender’s reputation and delivery success–no matter what ESP you choose.

What are you changing during migration?

Try not to alter too much at the same time when adjusting any email strategy. For example, if you’re looking to switch IPs, don’t also change sending domains at the same time. If you are only switching ESPs, it is a good idea to try and keep everything else constant if you are looking to compare your previous success with your new success.

If anything else is changing (i.e. list size, collection practices,) this will have an impact as well. When you switch ESPs, any differences may trigger sophisticated mailbox filters to reevaluate you more than they did with your legacy domains and IPs. Think of it like when you switch jobs in your career, your previous work at a company isn’t always considered in full, and you need to impress the new organization and coworkers/bosses.

Similarly, Gmail or Yahoo or Microsoft may have been used to some of the delivery metrics and recipient interactions with your mail, but since they update their reputation criteria often, they may be giving you a fresh review and this may lead to a temporary decrease in some metrics. As long as you keep up to date with the best email practices, this should level back out within a few weeks. Obviously this is a broad statement so feel free to ask questions of your new ESP account manager or delivery contact.

Changing ESPs won’t fix everything

The metrics discussed above will still be impacted at your new ESP if you are keeping any elements of your previous email program (same link domains, sending domains, image hosting domains, etc). While we mentioned that it is best to keep as many of those items constant for comparison purposes, we want to note that their reputation history doesn’t get wiped clean when switching ESPs.

Successful email programs do well because they send wanted mail and provide value. Their recipients are interacting favorably with the messages at a rate that ISPs like and therefore allow delivery of those messages to the inbox. Then, the chicken and the egg game resumes.

It’s always best for senders to remember this simple (yet sometimes difficult to master) idea of providing value to recipients through the messages you send. For more information and tips to improve your email deliverability, download SendGrid’s 2016 Email Deliverability Guide.



Jacob Hansen
Jacob comes from a background in technical account management and delivery analysis for the last six years, and has been with SendGrid's Deliverability Consultant team for the last two years. He enjoys spreading knowledge to help the email community send more "wanted email" and to help senders realize their full potential. Originally from Nebraska, but living in Colorado long enough for it to feel like home, Jacob enjoys a lot of what the Denver restaurant, bar, brewery and music scenes have to offer.