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Apr 20, 2021
Latest Update: March 2021
Email deliverability can really make or break an email marketing campaign. Most marketers know the theory behind boosting deliverability rates – maintaining clean lists, keeping subscribers engaged, building a good sender reputation, and so on. But many also know from experience that you can do everything by the book, and still have your emails mysteriously disappear after being sent.
Based on our email deliverability tests, we’ve confirmed what many marketers have long suspected – different newsletter services do have different deliverability rates. And the differences, in some cases, are quite startling.
As a result, we’ve decided to share our results, and have committed to performing regular tests to make sure our results are always up to date. We’ll continue to add them to this page with each round of tests.
Because we believe deliverability should be an important factor when deciding on which email tool is right for your business, we’ve also now added this as a criterion to each of our reviews.
Table of Contents
These rates represent an average derived from the five email deliverability tests in each testing round.
| Provider | Aug 2017 % | Mar 2018 % | Jan 2019 % | July 2019 % | Feb 2020 % | Sept 2020 % | Mar 2021 % |
|---|---|---|---|---|---|---|---|
| ActiveCampaign | 85.8 | 96 | 97 | 93.8 | 90.2 | 73 | 91.1 |
| AWeber | 80.3 | 79.8 | 75.6 | 80.4 | 85.4 | 83 | 77.6 |
| Benchmark | 63.9 | 75.8 | 49.2 | 41.8 | 45.2 | 66 | 75.1 |
| Constant Contact | 89.74 | 93 | 90.4 | 88 | 89.4 | 89 | 91.5 |
| ConvertKit | 92.1 | 88 | 81 | 91.4 | 60 | 95 | 96.3 |
| Drip | 89.14 | 89.8 | Not tested | 88.8 | 78.8 | 86 | 87.9 |
| GetResponse | 87.5 | 78 | 80.6 | 85.4 | 75.6 | 86 | 83.8 |
| MailChimp | 87.52 | 82.6 | 81.6 | 90.6 | 81.6 | 91 | 86.9 |
| MailerLite | 77.6 | 89 | 92.6 | 94.8 | 78.4 | 90 | 96.9 |
| Sendinblue | 83.9 | 75.6 | 77.4 | 88.8 | 95.4 | 76 | 96.3 |
| Mailjet | Not tested | Not tested | Not tested | 84.8 | 94.6 | 94 | 89.6 |
| CleverReach | Not tested | Not tested | Not tested | 79.6 | 80.8 | 93 | 94.3 |
| HubSpot | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 91.6 |
| Moosend | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 88.7 |
| Omnisend | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 85.1 |
| Mailify | Not tested | Not tested | 71.4 | 81.6 | Not tested | Not tested | Not tested |
| Newsletter2Go | Not tested | Not tested | Not tested | 83 | Not tested | Not tested | Not tested |
| Overall Average | 83.75 | 84.76 | 79.68 | 83.80 | 79.6 | 85.2 | 88.9 |
For an analysis of each of the individual test rounds, please follow these blog links:
Deliverability test March 2018
Deliverability test January 2019
Deliverability test February 2020
Deliverability test September 2020
Deliverability test March 2021
As you can see, deliverability rates can fluctuate over time. Even providers that have done consistently well (ActiveCampaign and MailerLite) have seen surprising results in recent rounds. There are also those that consistently perform pretty badly (Benchmark).
For an analysis of the most recent results, see the blog (and infographic) from our latest round of deliverability tests.
Across the board, the average deliverability was 88.9% in our latest round of tests. That means 11.1% of all emails are either completely missing or caught by the spam filters. Last round this number was 14.8% so we're glad to see more emails are getting delivered.
This is slightly better than the results achieved through Return Path's research, which found that the average global inbox placement rate was 83%, last year.
It’s no surprise that there’s a direct correlation between low deliverability rates, and high rates of email flagged as spam. Below is a breakdown of where exactly emails ended up (whether it was the main inbox, a secondary tab, spam folder, or if the emails went missing), in each test round we’ve completed.
Based on these results, we can start to see some general trends:
Thanks to Glockapps.com, we were able to see just how well each newsletter service performed in getting delivered to the four main ISPs – Gmail, Microsoft (Outlook and Hotmail), Yahoo and AOL. Based on our results, you can see that certain ISPs definitely look more favorably upon some tools than on others.
Please keep in mind that Glockapps sometimes adds or removes ISPs to reflect their current popularity on the market.
| Provider | Aug 2017 % | Mar 2018 % | Jan 2019 % | July 2019 % | Feb 2020 % | Sept 2020 % | Mar 2021 % |
|---|---|---|---|---|---|---|---|
| ActiveCampaign | 100 | 100 | 100 | 95 | 76 | 100 | 100 |
| AWeber | 100 | 100 | 100 | 83 | 81 | 92.6 | 92 |
| Benchmark | 50 | 100 | 0 | 13 | 34 | 100 | 100 |
| Constant Contact | 50 | 100 | 100 | 95 | 94 | 100 | 100 |
| ConvertKit | 100 | 100 | 100 | 95 | 80 | 100 | 100 |
| Drip | 100 | 100 | Not tested | 86.7 | 64 | 100 | 100 |
| GetResponse | 50 | 100 | 100 | 95 | 68 | 100 | 100 |
| MailChimp | 100 | 100 | 100 | 95 | 69 | 100 | 100 |
| MailerLite | 100 | 100 | 100 | 95 | 70 | 100 | 100 |
| Sendinblue | 100 | 100 | 100 | 95 | 93 | 100 | 100 |
| Mailjet | Not tested | Not tested | Not tested | 95 | 91 | 100 | 100 |
| CleverReach | Not tested | Not tested | Not tested | 89 | 82 | 100 | 100 |
| HubSpot | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 100 |
| Moosend | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 100 |
| Omnisend | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 100 |
| Mailify | Not tested | Not tested | 80 | 84 | Not tested | Not tested | Not tested |
| Newsletter2Go | Not tested | Not tested | Not tested | 95 | Not tested | Not tested | Not tested |
| Provider | Aug 2017 % | Mar 2018 % | Jan 2019 % | July 2019 % | Feb 2020 % | Sept 2020 % | Mar 2021 % |
|---|---|---|---|---|---|---|---|
| ActiveCampaign | 50 | 100 | 100 | 100 | 100 | 48.6 | 100 |
| AWeber | 0 | 18 | 0 | 56.9 | 60 | 61.4 | 24.3 |
| Benchmark | 0 | 0 | 0 | 33.8 | 23.1 | 51.4 | 71.4 |
| Constant Contact | 84.4 | 100 | 100 | 100 | 98.5 | 100 | 100 |
| ConvertKit | 84.4 | 69 | 75 | 95.4 | 0 | 100 | 98.6 |
| Drip | 0 | 100 | Not tested | 100 | 100 | 94.3 | 100 |
| GetResponse | 50 | 20 | 20 | 60 | 56.9 | 80 | 60 |
| MailChimp | 50 | 24 | 31 | 80 | 80 | 80 | 60 |
| MailerLite | 0 | 100 | 100 | 100 | 32.3 | 61.4 | 100 |
| Sendinblue | 50 | 7 | 0 | 78.5 | 98.5 | 100 | 100 |
| Mailjet | Not tested | Not tested | Not tested | 43.1 | 100 | 100 | 71.4 |
| CleverReach | Not tested | Not tested | Not tested | 100 | 63.1 | 98.6 | 98.6 |
| HubSpot | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 94.3 |
| Moosend | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 98.6 |
| Omnisend | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 80 |
| Mailify | Not tested | Not tested | 16 | 75.4 | Not tested | Not tested | Not tested |
| Newsletter2Go | Not tested | Not tested | Not tested | 100 | Not tested | Not tested | Not tested |
| Provider | Aug 2017 % | Mar 2018 % | Jan 2019 % | July 2019 % | Feb 2020 % | Sept 2020 % | Mar 2021 % |
|---|---|---|---|---|---|---|---|
| ActiveCampaign | 100 | 100 | 100 | 100 | 90 | 91.1 | 82 |
| AWeber | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Benchmark | 100 | 100 | 100 | 20 | 7.5 | 20 | 40 |
| Constant Contact | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| ConvertKit | 100 | 100 | 97.5 | 100 | 97.5 | 100 | 100 |
| Drip | 100 | 100 | Not tested | 100 | 100 | 100 | 100 |
| GetResponse | 100 | 97.5 | 100 | 95 | 100 | 100 | 100 |
| MailChimp | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| MailerLite | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Sendinblue | 100 | 100 | 97.5 | 100 | 82 | 0 | 100 |
| Mailjet | Not tested | Not tested | Not tested | 100 | 100 | 95.6 | 82 |
| CleverReach | Not tested | Not tested | Not tested | 100 | 87.5 | 97.8 | 100 |
| HubSpot | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 98 |
| Moosend | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 100 |
| Omnisend | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 100 |
| Mailify | Not tested | Not tested | 80 | 85 | Not tested | Not tested | Not tested |
| Newsletter2Go | Not tested | Not tested | Not tested | 60 | Not tested | Not tested | Not tested |
| Provider | Aug 2017 % | Mar 2018 % | Jan 2019 % | July 2019 % | Feb 2020 % | Sept 2020 % | Mar 2021 % |
|---|---|---|---|---|---|---|---|
| ActiveCampaign | 7.1 | 100 | 100 | 100 | 97.1 | 0 | 100 |
| AWeber | 100 | 100 | 80 | 100 | 100 | 100 | 100 |
| Benchmark | 0 | 80 | 100 | 20 | 0 | 20 | 40 |
| Constant Contact | 92.9 | 100 | 100 | 97.1 | 100 | 100 | 100 |
| ConvertKit | 100 | 100 | 100 | 100 | 97.1 | 100 | 100 |
| Drip | 100 | 100 | Not tested | 100 | 85.7 | 74.3 | 71 |
| GetResponse | 85.7 | 100 | 100 | 94.3 | 100 | 100 | 100 |
| MailChimp | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| MailerLite | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Sendinblue | 85.7 | 100 | 100 | 100 | 100 | 0 | 100 |
| Mailjet | Not tested | Not tested | Not tested | 100 | 100 | 57 | 94 |
| CleverReach | Not tested | Not tested | Not tested | 17.1 | 100 | 94.3 | 100 |
| HubSpot | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 83 |
| Moosend | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 100 |
| Omnisend | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 100 |
| Mailify | Not tested | Not tested | 74.3 | 62.7 | Not tested | Not tested | Not tested |
| Newsletter2Go | Not tested | Not tested | Not tested | 57.1 | Not tested | Not tested | Not tested |
What does this mean? Well, if you have a good sense of who your subscribers’ email providers are (in an ideal world for email marketers, that would be Yahoo!), you might consider choosing a newsletter service based on this. Of course, that’s often difficult to know. Plus, as our results show, deliverability to ISPs can change over time.
It’s perhaps more useful to just keep an eye out for any red flags. For example, Microsoft has, in the past, applied more stringent filtering to inbound emails, and some newsletter services – such as Benchmark – still struggle to get through. Though it has been slightly easier to get emails through to Microsoft more recently, your deliverability rates may still be suffering when sending to this ISP.
While the newsletter services were generally able to deliver to Gmail mailboxes just fine, not all ended up in the Primary tab. Perhaps this isn’t a surprise to anyone who’s used MailChimp, but our tests found that MailChimp had a higher chance of getting relegated to a Promotions tab – even with emails that wouldn’t normally be considered ‘promotional’.
| Provider | Aug 2017 % | Mar 2018 % | Jan 2019 % | July 2019 % | Feb 2020 % | Sept 2020 % | Mar 2021 % |
|---|---|---|---|---|---|---|---|
| ActiveCampaign | 0 | 0 | 0 | 0 | 60 | 40 | 40 |
| AWeber | 0 | 0 | 60 | 18.7 | 0 | 74.1 | 55 |
| Benchmark | 20 | 0 | 0 (100% went to spam) | 6.7 (87% went to spam) | 20 (66% went to spam) | 74.3 | 80 |
| Constant Contact | 11.4 | 0 | 0 | 20 | 91.4 | 40 | 40 |
| ConvertKit | 0 | 0 | 60 | 20 | 34.3 | 40 | 60 |
| Drip | 0 | 0 | Not tested | 14.7 | 20 (36% went to spam) | 40 | 40 |
| GetResponse | 0 | 0 | 0 | 20 | 52.1 | 100 | 100 |
| MailChimp | 100 | 100 | 60 | 20 | 0 (31% went to spam) | 60 | 60 |
| MailerLite | 0 | 0 | 60 | 33.3 | 60 | 80 | 80 |
| Sendinblue | 22.9 | 0 | 60 | 0 | 12.9 | 20 | 20 |
| Mailjet | Not tested | Not tested | Not tested | 40 | 42.9 | 60 | 60 |
| CleverReach | Not tested | Not tested | Not tested | 14.7 | 0 | 40 | 60 |
| HubSpot | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 80 |
| Moosend | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 40 |
| Omnisend | Not tested | Not tested | Not tested | Not tested | Not tested | Not tested | 40 |
| Mailify | Not tested | Not tested | 40 | 12 | Not tested | Not tested | Not tested |
| Newsletter2Go | Not tested | Not tested | Not tested | 54.7 | Not tested | Not tested | Not tested |
There’s no telling why some providers get sorted to Promotions and others don’t, as Google’s complex sorting algorithm is kept tightly under wraps. Ending up in Promotions is less than ideal, as your email is likely to get lost in the flood of emails that often make their way to that tab. Then again, if your email really is promotional and your subscribers are used to accessing emails from that tab, it may not be a problem. Furthermore, your email would be better off landing here than in the spam folder, which is what has happened to many providers in previous rounds.
Our tests looked at some of the most widely-used newsletter services:
Using Glockapps.com, we ran our first round of testing in August 2017. This round comprised of 5 separate tests conducted over several weeks. We wanted to make sure all conditions were equal, so in each test, we:
Over three thousand emails later, we finally had the results from our first testing round. And we found some pretty big differences in deliverability rates between providers – ranging from 64 to 92 percent!
We repeated this very same test round in March 2018, and from July 2019 onwards, we included an HTML email as one of our tests. The latest deliverability test we carried out was in March 2021 and we plan to conduct, on average, one every 6 months.
We’d love to know what the top performers' secret is – and we’re sure the other tools do too! What we do know is that the ISPs often have the last say on whether an email lands in an inbox. This means that they have to trust the mail server sending that email; in our case, that means the server used by the newsletter service.
If that same server also happens to be sending out emails for other clients that are considered ‘spammy’, deliverability of your own emails could suffer. Newsletter services, therefore, make it a priority to maintain their server’s reputation. But some are clearly doing a better job of this than others.
When choosing a newsletter service, there are obviously many factors to consider – price, features, usability, and so on. But with these results, we’ve hopefully made it easy for you to shortlist (or discard) a few based on potential deliverability.
Note that we said ‘potential’ – there’s simply no way of knowing for sure how deliverability will play out for each business. Our results can give you a general idea of what you can expect, and what things to look out for, but your own experience may be very different. If so, we’d certainly like to hear about it!
In spite of our best efforts to establish the same testing conditions for each tool, it’s true that other factors can play an important role. As the sender, you have a responsibility to do your best to increase deliverability by authenticating emails using SPF and DKIM and following best practice guidelines for creating and sending emails. Here are a few other pointers to bear in mind:
Try to only send emails people actually want to receive, i.e. only send to fully opted in lists. Sending emails to non-permission based lists will result in low open rates, high unsubscribe rates, and high spam complaints, all of which indicate an unsuccessful email.
These kinds of results can have a negative effect on sender reputation and will impact future deliverability.
Find the right balance between sending too many and too few emails to your subscribers. Remember that people are bombarded with tons of emails on a daily basis, so, in order to avoid inbox fatigue, only send what’s necessary.
You can even ask them to set the frequency at which they’d like to receive emails from you in their preferences. This can avoid spam complaints.
It’s not a good idea to have inactive people on your list as, if you’re sending emails to them regularly, this can affect sender reputation and impact deliverability.
Make sure to regularly check in with the less active people and give them the opportunity to re-engage or opt-out of future emails.
