How to Monitor 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. In addition, sending to an engaged segment can help improve your deliverability.

Monitoring Your Deliverability in Response to Apple iOS 15 Changes

With the September 2021 release of iOS 15, macOS Monterey, iPadOS 15, and WatchOS 8, Apple changed how they handle email privacy. This will affect any email client checked via the Mail App on the Apple iPhone using iOS 15.

These changes could not only impact how you track subscriber engagement, but how you monitor your deliverability and reputation overall. We suggest following the steps below to ensure you are on top of your deliverability best practices.

Expand Your Engaged Segment

For deliverability monitoring, it will be key to focus on other metrics besides opens to inform you if subscribers are actually engaged with your brand.

Engagement data like clicks, purchases, on-site activity, and mobile interactions will help you understand if your customers are actually interacting with your brand. If you are not using these metrics already, you will want to expand your engaged segment in Klaviyo to include them.

In addition, if you have any Flows that trigger based solely on email opens, consider expanding that trigger definition to include other engagement criteria like clicks or product views.

Remove Unengaged Segments

Once you have widened your engagement criteria, it’s important to also look at subscribers that may be unengaged.

With these changes to Apple Mail opens, we suggest creating an unengaged segment that includes at least clicks. As you continue to monitor your unengaged segment, you may want to expand this to include subscribers that were not active on site and did not make purchases.

Actively Monitor and Clean Your Lists

Besides simply monitoring your unengaged subscribers, it’s important to regularly try to re-engage these people or even completely remove them from your lists. Regular list cleaning will ensure that you’re only contacting people who want to hear from you and help you maintain a strong reputation.

How to Monitor Key Metrics

With Campaign Reporting

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

With Benchmarks

Another way to monitor your email deliverability performance is to analyze your deliverability-specific benchmarks. Klaviyo’s benchmarking tool allows you to evaluate and compare your data in relation to Klaviyo deliverability best practices, overall industry trends, and peer groups (i.e. companies similar to your own). Use this tool to take note of how your deliverability performance relates to others and Klaviyo guidance, to determine where you can improve.

Benchmark Prerequisites

In order to see benchmarks, you must meet our eligibility requirement of having sent at least twenty-five emails in the last six months. Any account that provides its industry will be able to see industry-level benchmarks. Benchmarks are updated with new data on the tenth of every month. You will see a timestamp of when your benchmarks were last updated in the upper right. If you become eligible for benchmarks this month, your benchmarks will not be available until next month

Part of how Klaviyo formulates peer group benchmarks is by using information on your industry and vertical. Your industry and vertical information is stored on the organization contact information page. It is important to keep this information up-to-date if it is not already. For details on how to update this organizational information, head to How to Update Your Industry and Vertical in Klaviyo.

Email Performance Benchmarks

First, head to Analytics and select Benchmarks.


Within Benchmarks, there are four separate pages where you can analyze your data. By default, you’ll be directed to the overview page. Select Email Campaigns from the main tab to hone in on your email marketing and deliverability performance.

Campaign Table

By default, your Email Campaigns page will show a table view as shown in the example below. 


You can also choose to expose the data for percentiles by toggling the option for Detailed View on the upper right side.


In these tables, take note of what your value is for various performance indicators (e.g., open rate, click rate, bounce rate, etc.). Compare your data with the recommendations in the table above, and make changes where needed to boost your deliverability. For a complete listing of all the metrics on the Campaigns Performance page and what they mean, head to our Guide to Benchmarks in Klaviyo resource.

Moreover, you should strive to have a status of Excellent or Good for each performance indicator. If your status is Poor or Fair, make efforts to improve. Head to How to Improve Your Benchmarking Performance for more information. 

Campaign Graph

On the Email Campaigns page, you can monitor how your campaigns perform over time, customizing the performance indicator, timeframe, and graph to focus on. 


Additionally, by hovering over any of these graphs for your campaign performance, you will see a breakdown of how your performance rating status  (Excellent, Good, Fair, or Poor) was derived. Your rating will be a mix of Klaviyo best practices for benchmarks, peer groups, and overall industry statistics.


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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