How to setup an A/B test email campaign

How to setup an A/B test email campaign

You asked, so we are answering! Until there is an automated A/B testing offered via the platform (planned for end of March 2023) you can quite easily setup A/B tests manually.

TIP: You can setup an AB test manually on any ESP that supports segmentation but doesn’t offer auto AB testing. 

What Is an A/B Test Campaign?

An A/B test campaign is a campaign with 2 or more versions being tested on one dimension – typically subject line or send time. A multi-variate test is a test with more than 1 dimension, for example if you are testing 2 different subject lines with 2 different versions of your message body you have 4 total versions and a multi-variate test, to determine the best combination of subject line and message body.

Why Use AB Tests?

AB tests can help you optimize your campaign engagement, by determining best time or subject line to use. If you have a large list (over 50k) you can test a subject line on 20k and use the best one on the rest of your list, improving your engagement overall.

You can setup AB test to determine:

  1. Ideal send time for your brand or list – test early on, then use that knowledge forever!
  2. Best subject line
  3. Best converting CTA in your email body
  4. A combination or all of the above!

Besides producing better results (sales, conversions), higher engagement helps improve your future inboxing.

How to Setup an A/B or A/B/C Test

Step 1: Setup up your A/B or A/B/C segments

Determine how many variations do you want to test – that’s how many segments you need to split your list into. We suggest to define reusable segments using “starts with” condition on one of your custom fields, for example first name.

Random segment example

Then, create a segment that’s basically “not A” to ensure you don’t make a mistake with rule overlap. The example below shows a segment C that’s basically doesn’t match ether A or B, and segment B would be setup similar to A but with different rules.

Random segment B

TIP: Make sure each segment has at least 10,000 contacts in it, so your experiment results are statistically significant.

Step 2: Setup your campaign variations.

Create your bulk/promo campaign, then create copies with your variation – subject line, preview, or message body. Assign a different segment to each campaign, see example in the screenshot below.

AB segment assignment

If you are testing on send time, then your campaigns will be identical, but will just be scheduled to send at different times.

Manual AB test example

Note: The example above is for a B2C list that’s 60%+ Gmail, so those landed in Promotions tab.

TIP: You could create a test using small parts of a larger list, then use the results for the remainder of your list. 

Step 3: Start Testing (almost)

Reach out via chat and request to update your account to allow you to send more than 1 campaign at a time, if you want to test on content and send your campaigns at the same time. By default, accounts have 1 queue and campaigns go out sequentially. If you are on an Agency plan, you already have ability to send concurrent campaigns.

That’s it. If you are a BigMailer customer you can reach out for assistance with this or anything else via chat 7 days a week.

Not a BigMailer customer? Why not try BigMailer for free, with no features locked? We are sure you will love it.


High complaint rate on Feb 20 for Hotmail, MSN, Live

High complaint rate on Feb 20 for Hotmail, MSN, Live

Many customers who sent campaigns on Feb 20 reported high complaint rates. Upon further review of engagement by domain reports we are able to confirm that the complaint rates went up significantly for these email domains –,,,,

Why did this happen?

It appears there was a change in the Hotmail algorithm that determines what email go to spam folder vs. inbox. As a result, 3 things happened:

  • A very high volume of spam is been seen in the Inbox.
  • Regular senders inboxed more of their emails than they did historically, seeing higher open rates and as a result higher complaint rates.
  • Some subscribers had to mass move emails to Spam folder or marked large batches of emails as Spam, likely marking some emails as spam without high intent.

What should you do?

Consider using segmentation and exclude high complaining domains in the next 1-2 days to lower your overall complaint rates, whether you are using Amazon SES and worried about suspension or just want to avoid getting caught in the crossfires.

As always, to keep complaint rate low, follow these email deliverability best practices:

  1. Make your unsubscribe link east to see/find, don’t make the text small
  2. Consider lowering your frequency if your complaint rates are high.

To ensure you maintain high deliverability and inboxing follow best practices. If you think you already do, please review this article on advanced deliverability and inboxing tips.

If you are a BigMailer customer and need assistance or would like an audit of your account please reach out to us via chat.

We will be posting updates here if you want to know when this issue gets resolved.

Email Verification Service Provider Comparison

Email Verification Service Provider Comparison

Email deliverability has been a hot topic for marketers for quite some time. With mailbox providers getting more aggressive about their spam blocking and filters, inbox placement has become a priority issue for many marketers to address. To protect their email deliverability, marketers need to implement email verification as part of the pre-campaign routine. In this article, we are comparing a few email verification service providers to help you find the one that will keep your email list clean.

Why Verify Your Email List?

Email deliverability is a complex topic, but it comes down to 3 things:

  1. Sender reputation, this includes sender email/domain as well as IP address it sends from.
  2. List and content quality.

So deliverability is strongly correlated to your sender reputation and hard bounce rate is one of the factors affecting it. With high hard bounce rates sender reputation takes a hit. If you don’t implement any actions to reduce your bounce rate it can negatively impact your inbox placement. Your domain might get marked as SPAM by Internet Service Providers, which can result in your emails being delivered to the SPAM folder, and even lead to getting your domain appear on blacklists.   

Risk of Account Suspension with Your ESP

An average email list decays at a rate of 2% per month for B2C lists and 3% for B2B lists. So if an email list hasn’t been engaged in more than 3-4 months it can have more than a 10% bounce rate on the first bulk campaign. A bounce rate over 10% can result in getting an account suspended on many email platforms, in addition to causing long-term damage to your sender reputation. 

About Catch_all and Accept_all emails

Email verification will also prevent you from sending your campaign to disposable (aka temporary) emails as well as emails that domains set up as catch_all. Disposable emails are often used by spammers and fraudsters. Once created they usually are valid for around 48hrs, and later become invalid emails that will generate hard bounce. Catch_all also known as Accept_all emails, is an address that is specified to receive all messages that are addressed to an incorrect email address for a domain. The risk with such emails is that it might seem to be valid, however, it could still generate a hard bounce. By using email verification you will be able to establish which of the addresses are set up as catch_all, but you won’t learn if it is deliverable or not. The decision to message such addresses should be based on the overall quality of your list.

Email Bounces and Cost

There is of course a budget factor – email verification can save you money. Sending your campaign to undeliverable or risky addresses via your ESP’s or marketing platform can generate extra costs, with no chance of generating any return on investment (ROI).

Verification Process and Results

In a typical verification process you upload a CSV file and once validation is complete you see stats on the results and options to download your verified list. Most verification services produce at least these 4 statuses:

  1. Deliverable – these emails are safe to send to
  2. Undeliverable – these addresses no longer exist and should not be sent to
  3. Risky – these emails are likely to result in a high bounce rate (often catch-all addresses)
  4. Unknown – these emails couldn’t be verified so may result in high bounce rate.

If your email verification provider allows it, you should download Deliverable, Risky, and Unknown as separate lists and upload them as separate lists into your email marketing platform. If you are starting fresh with a new service provider you should ONLY send your 1st campaign to Deliverable addresses only, to ensure the lowest possible bounce rate. This is because many providers move you onto a shared IP pool tier that correlates to your 1st campaign or campaigns sent in the first 1-2 days.

On average, email lists identified as Risky or Unknown by email verification providers result in 30% bounce rate, so they should be slowly added into large bulk campaigns overtime, to finalize verification through sending.

While bounce rate below 10% will not result in you getting banned from an email marketing platform your goal should be to keep bounce rate below 3% for best email deliverability.

Choosing an Email Verification Service

There are a lot of email verification services available, and it might be overwhelming when searching for the right one for the first time. There are several methods used by providers to verify emails so there is a small variation in results and accuracy. We find that the difference in accuracy is fairly small – around 2% – while the cost can vary x2-5.

For this comparison article, we are focusing more on affordable providers we have evaluated as potential partners. BigMailer is a very affordable email marketing platform, so it was important for us to continue to offer our customers great value when integrating a 3rd party email validation service. 

Other factors that we considered besides cost are: security and GDRP compliance, availability of robust APIs to process large data sets, possibility to run a test prior to purchase, and finally the team behind the service and support. 

Below are the services we had reviewed and ranking factors we have checked for this article:

email verification provider comparison 2022

Last Updated: Mar 14 2022

As we were evaluating prospecting partners 2 services stood out (and we got you extra discount with both):

Bouncer verification resultsBouncer

Bouncer has easy-to-use UI and very flexible data download options, making it our favorite. You even get options on what columns to keep or add to your final verification results, which can simplify your workflows post verification. These options are especially helpful for large list owners, since large data files can become a blocker for importing a list into an email marketing platform.

Bouncer offers you an option to run a free bounce rate estimate, which helps you decide if you need to verify your list. The estimate only takes a few min to generate and can be incredibly useful.

Bouncer team and servers are located in Europe so this can appeal to organizations in the EU region. Bouncer file upload limit is 500,000 emails or 30MB in file size. Get a 10% discount with this link.


Emailable offers good verification speed on large lists and 1500 free validation credits to BigMailer customers via this link only. Emailable file upload limit is 1 million emails and 100MB in file size, which can be useful for large list owners. 

We also like Emailable Deliverability Monitor service – $149/month for up to 50 domains/IPs with 12-hr checks.

Both providers have de-duplication but they act on it differently:

  1. Emailable automatically de-dupes your list but doesn’t display the info on results so it can be confusing why your output list is smaller than the list you uploaded.
  2. Bouncer automatically de-dupes and displays the stats.

Neither service is offering ability to identify spam traps, a feature very few providers offer at a higher than usual verification cost.

About Spam Traps

Spam traps are used to identify and monitor spam email by Internet Service Providers (ISPs), anti-spam organizations, and blocklist operators. They are email addresses (also called honeypots) used to identify senders who aren’t following email best practices. If you either purchase your email lists or scrape email addresses from the web there is a good chance you have a lot of spam traps on your list. 

Learn more about avoiding, identifying and removing spam traps in our article on spam traps. If you are a BigMailer customer you can reach out to us to help you determine if this is an issue for you and what provider would be best for removing spam traps from your list. Not a BigMailer customer? Get started with a free account.

Happy email marketing!