Monitoring Email Deliverability Performance

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As you regularly review your campaign performance, it's a good idea to ask yourself the following questions to remain diligent regarding email deliverability issues:

  • Do I have a high rate of spam complaints?
  • Do I see a high rate of bounces, consistently?
  • Are my open rates falling into single digits?

How to Evaluate Your Deliverability

There are a lot of numbers in your Klaviyo account, so you might be wondering what good deliverability looks like. When we advise customers on deliverability we look at the following ranges for key email metrics.

  Unique Open Rate Unique Click Rate Bounce Rate Unsubscribe Rate Spam Rate
Great 25% or more 2.5% or more Less than 0.4% Less than 0.2% Less than 0.05%
Proficient 15-25% 1.5-2.5%   0.4-0.8% 0.2-0.3%  0.05-0.08% 
Room for Improvement 10-15% 1-1.5% 0.8-1.5% 0.3-0.7% 0.08-0.15%
Critical Less than 10% Less than 1% 1.5% or more 0.7% or more 0.15% or more

Monitor these ranges based on the last three campaigns you have sent. If the averages fall in the yellow or red ranges, you should take action.

Send to an engaged segment to improve your deliverability.

How to Monitor Key Metrics

Use the following key metrics to evaluate your deliverability performance. These can be found by navigating to your Campaign Trend Report. This is your main report where you can monitor opens, clicks, bounces, and spam.


  • Unique Open Rates: the number of individuals opening your email divided by the number of recipients (as opposed to total opens, which measure the total number of times an email was opened)
  • Bounce Rate: the number of bounced addresses divided by the total number of recipients
  • Unsubscribe Rate: the number of recipients who unsubscribe divided by the total number of recipients — this is measured on a per campaign basis, or you can view the list growth report for a particular list


You can also create custom reports for campaigns, honing in on the metrics you care about most and viewing how they change over time. To do so, head to Analytics > Custom Reports, and create a new Campaign Performance Report

Spam Issues

Spam complaint rates are calculated by dividing the number of spam complaints about a particular email by the total number of recipients.

If you have a high spam rate, there are two key steps you can take:

  1. Conduct spam tests: services like Litmus will help you check whether or not an email is ending up in the spam folder by using a series of standard filters and testing with the average inbox for Gmail, Yahoo, AOL, etc.
  2. Identify problematic lists and/or email addresses: if you think emails sent to certain lists are going to the spam folder and that these lists might be the source of your issue, test your theory. A "problem list" could originate from a competition you ran, an event you held where you collected emails, or a list you haven't emailed recently. If you think a specific domain is the culprit (e.g., Gmail can often be more restrictive), we recommend using our segment builder to explore and validate (or invalidate) your concerns.

Use the following process to identify problematic lists and email addresses:

  1. Create a segment specifying that someone meets the core condition you'd like to test — for example, they have a email address or are on the list that you created for a specific competition.
  2. Add a second condition to the segment with the condition: has opened an email at least once over all time.
  3. Repeat this process for people not in the first group (i.e. use these same parameters to exclude subscribers who are in the first segment).
  4. Compute open rates to see if the open rate for your test list is actually much lower than the open rate for your other lists.

Additional Resources

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