3 Reasons Why You Should Use a Single List in Klaviyo | 2024

3 Reasons Why You Should Use a Single List in Klaviyo | 2024
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Time and time again, we have seen clients of all sizes mis-manage their data and misunderstand overall list hygiene and efficiency. More times than not, the mismanagement of list hygiene is initially sparked by a poor, or limited, understanding of how lists work within Klaviyo, as well as effective segmentation strategies.

The dangers of having an account with dozens, or even hundreds, of independent lists is that they are incredibly messy, hard to navigate, manage, maintain healthy accurate data and illogical. 

Undoubtedly, any business or client that is collecting email data from their audience and assigning those profiles to many lists, will be increasing their workload and decreasing their results and return on investment. The solution - streamlining your data into a single, consolidated, master list with properly applied segmentation strategies. Only then will you alleviate the headache resulting from messy data collection and ultimately begin to reap the benefits and rewards from effective email marketing. Because of this fundamental approach to data management, at Magnet Monster, we always prioritise this aspect of any Klaviyo account from the offset no matter the size of the business.

Single-List Approach

Essentially, the single-list approach quite simply means that you have one main master list where you streamline all of your contacts into allowing you to optimise your marketing efforts, deliverability and reporting.

Once you have one main master list, you’re able to define and spread out into buckets of profiles into relevant segments in any dimension and for any need clearly, cleanly and concisely.

The alternative to this approach is to have various entry routes pulling data into multiple or many lists, fragmenting your data, making it very difficult as time progresses and lists grow to manage all these sources of data into anything remotely useful.

Now, there are times and scenarios where multiple-lists are useful and should be used, however, in most instances and the majority of cases, the single main master list approach is best practice.

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Why Use One List?

Imagine if you were, that your database of profiles is offline. Would you rather have one filing cabinet, with drawers sensibly sorted, and within each drawer folders clearly labelled containing all of your specific files - for easy access, navigating, sorting and maintenance? Well, it’s the same for online data.

The alternative to this, is having a building full of many, many different filing cabinets, unrelated to each other, filled with different drawers, different folders, and different purposes - all of which unrelated to each other in any way meaningful.

Wouldn’t it be easier to have one filing cabinet, with all of the relevant data stored within it, easily accessible and manageable, whereby you can allocate drawers/folders and so on, to have useful meaning within that cabinet of data that it houses? You’re not going to be trying to remember where all the different filing cabinets are, what they each hold, the purpose, and how those files within them inter-relate to each other.

Already, you’re probably building up an image in your mind of how data management is handled online, and the risks of managing multiple lists, when on the side of sanity, you could have one list, well maintained for any purpose.

There are several reasons why using a single main list is beneficial. Having a single main list will help you:

  • Maintain good data hygiene
  • Access list growth visibility
  • Optimise deliverability

Learn more about each in the sections below.

Essential good data hygiene

Critical to any email marketing strategy is the requirement (more now than ever for maximum deliverability into the inbox) for your data to be error-free and up-to-date. Having one main, master list, would mean that your profiles exist only in one place and are always a single instance of each emailable contact. 

Conversely, when you have multiple lists, a profile could be assigned to more than one list which means if you email to multiple lists, there’s a risk that you’ll end up repeating messages in various permutations of similar themes and potentially overwhelm portions of your audience.

By utilising one streamlined master list, you are better able to track and organise who you are messaging and how. 

To become more granular and specific (as you should) then it is far easier to segment relevantly all of this data from one list, rather than trying to pull in segments together from various list sources, especially if you have many lists. 

Segments update dynamically over time based on the behaviours of your subscribers.

List growth visibility and reporting

Importantly, for every list inside of Klaviyo you can access a growth report to gather metrics on list growth over time. Where having one main master list allows for you to see regular improvements, and changes on a macro large scale and gathering an insight into subscriber behaviour over time, trying to consolidate and track this accurately across multiple lists is chaotic and less accurate.

3 Reasons Why You Should Use a Single List in Klaviyo | Magnet Monster
A screen grab of a sample email marketing list in Klaviyo

Deliverability Optimisation

Now, more than ever with recent updates and changes to major EMS providers algorithms (like Gmail) clean lists are critical to deliverability and inbox placement. Much like the world of SEO, delivering mail into the inbox and diverting away from the spam box requires diligent efforts on the part of the email marketing team - and that means clean lists are of paramount importance.

Having just one main master list is far easier to cleanse and streamline the cleaning process, than trying to perform list cleaning on many unconnected lists. By having just one consolidated point of data, you can easily remove outdated, unengaged and bounced profiles efficiently.

Once you have a clean and consolidated point of data in one list, you can begin to effectively segment that data so that you can send relevant, meaningful and engaging messaging to appropriate profiles in your pool of data. As an absolute minimum effort, you would want to set up an engaged segment of the main list.

Where you might have multiple lists, and profiles subscribed to many lists, it becomes far more difficult to consolidate and segment engaged users effectively and accurately - and that problem is exacerbated by adding more and more lists endlessly.

Eventually, it would become an impossible task and prone to many errors and inaccuracies.

Plus, for pure sanity, your list of conditions on your engaged segments would be bloated, messy and hard to follow logically as time progressed.

Differences between lists and segments

For many, a point of confusion is the differences between lists and segments, and many do not understand the actual fundamental differences that are distinct between the two pools of data.

Ultimately, once you have all your data in one list, segmentation is the absolute most important aspect of your Klaviyo or email marketing account. 

With well thought out and executed segmentation strategies, you can get extremely granular with your data - which allows you to be an expert at data-driven marketing in real time.

A segment is a combined pool of data that you pull out of your master via a set of given conditions. It’s like reaching into that filing cabinet we mentioned earlier, and grabbing all the folders from the top 3 drawers that are green and labelled ‘customers who have previously purchased in the last 10 days’ as an example. You’re literally using a set of conditions to reach into the big repository of information and just grabbing the exact sets of data that meet your requirements.

3 Reasons Why You Should Use a Single List in Klaviyo | Magnet Monster
Screen grab of segmenting users in Klaviyo based on their activity

As an example, a segment of your list could include everyone who has purchased, has visited your website in the last 7 days, opened emails more than 3 times historically and are resident in the USA, while giving consent to be marketed to. An important distinction for segments, is that they are dynamic, and update in real-time on the fly. So if someone meets your conditions today, they’ll be included in that segment, but if they do not meet your segment conditions at some point in the future, they’ll drop out of the segment, and vice versa for people who become eligible to meeting your criteria. This means that segments shrink and grow intelligently and on demand for the point in time that the conditions are querying the list.

Conversely, lists are static repositories of raw data. They do not shrink or grow dynamically based on any conditions, people just keep getting added to lists over time (or shrink if profiles unsubscribe), including profiles without consent, bounced emails, emails incorrectly spelt and so forth, which is why it is critical to maintain proper list hygiene.

Users have a choice whether they remain subscribed, or unsubscribed from a list - which means if the customer is unknowingly subscribed to many lists, they may unsubscribe from one list, but remain subscribed to another, or many other, lists - whereby they will still probably receive marketing from you, potentially leading to confusion and frustration from your customer base. This cannot happen with one main master list, they are either subscribed or they are unsubscribed.

Segments however, are not operated or influenced by the customer directly (unless they become unengaged and that’s a condition, or, they unsubscribe in which case you can’t email them anyway). In this regard, segments will pull profiles in accurately based on actual data that meets conditions, and not user influenced by choice, it is the conditions put in place, that determine who will be included in, or excluded from, a segment you create.

So, now that you know you can pull profiles dynamically for any condition from one repository, the master list, the options are literally limitless with how you define those conditions and thus define the segments you’re seeking to use in targeted marketing.

Segments are typically used for a number of purposes, such as:

1. To send very targeted campaigns

Rather than emailing your entire list (an old school approach of throwing everything at the wall and seeing what sticks - a method that will this day lead to poor deliverability and eroded success over time in most instances), you can use segments to build meaningful cross-sections of your list, to send relevant content and drive up engagement & bring in a more focused and measurable return on your marketing efforts.

2. To trigger email flow automations

Where you would like to trigger an automated sequence of messages via a flow, when profiles meet certain criteria through the set of conditions outlined in your segment (for example - profiles who have been a customer and purchased 3 times in the last 3 months specifically). Here you can trigger an automated sequence of messages when people reach that criteria and are pulled into that dynamic segment you have set up.

3. For analysis and reporting

As segments are dynamically updated automatically in real-time, they provide an accurate and up-to-date clear picture of your audience and their behaviour, which makes it ideal for reporting, analysis and further decision making. This is not possible with static lists.

Segments can also be used to assist with a number of other critical marketing activities such as list cleaning, cross-sells and loyalty programs etc.

Using $source to track data acquisition

One of the main reasons we see for people setting up multiple lists and continuing to set up multiple lists is because they do not understand the fundamental differences between lists and segments, nor how data is either shared and useful, or isolated in silos and less useful.

A major driver for many people to set up lists is to keep track of where inbound data has come from. For example, we’ve seen clients set up lists for external apps, Facebook ads, Google ads, Bing ads, offers and promotional special offers, in-store sign-ups, events and expo signups, competitions, ambassador leads and so on etc.

3 Reasons Why You Should Use a Single List in Klaviyo | Magnet Monster

When discussing consolidating all data into one list, one main challenge that prevents people from making the switch, is their reluctance to pool all data into one repository - one list, as they’re frightened they’ll lose track of the inbound source of that data. This concern is a mute point, as it’s actually irrelevant.

For this purpose, we use the $source profile property at all times. The $source profile property helps you to better understand exactly where your inbound data is coming from. In regards Klaviyo, natively, a $source property is added to profiles under many natural conditions, and where not, you can nearly always define and include this in all of your inbound data acquisition.

In a real world setting, if you wanted to track all the users who have subscribed to your master list coming from an external competition landing page, this is simple. You pass the data across to Klaviyo with the required hidden $source field upon form submission (sign-up) and then as the user profile is added to the master list, so to is this database field for the $source (where they came from). From here, you can build dynamic segments, using the condition that filters for that source, and instantly you have a dynamic, real-time update of all of they users who have signed up from your external competition landing page in this example.

It is far easier, cleaner and more accurate to manipulate your data in this way, than having tens or hundreds of siloed lists that do not have any overall connections to each other.

In 9 cases out of 10, this is the ideal way to manage your inbound data into Klaviyo and how it is best managed for the above reasons.

There are however, instances where it may not be possible, or is desired specifically, to separate out data into other lists - though ultimately your goal should be to have as few lists as possible, and managed in the most logical and streamlined way possible.

When to use multiple-lists

It is occasionally not possible to define which list incoming data is assigned to, and frustratingly, not all 3rd party integrations on the market have the ability to pass data across to Klaviyo where you define a $source or specific list. However, where it is possible, you should.

Other reasons to use separated lists (though again, it’s not always essential if you properly $source tag and segment your main list dynamically) could be to separate out trade/offline customers in an isolated and siloed fashion, or potentially, in-store bricks and mortar specific customers.

In these cases, it maybe that your in-store customers or your wholesale trade customers have different consent conditions to what messages they accept to receive and under what conditions, compared to your e-commerce or online based customers. You may also drive very different content, different product offerings and/or different catalogues and pricing entirely to these audiences and so in some instances or cases it may be relevant and sensible to separate out your lists.

All of that being considered, we have never come across a case where even the largest of brands and clients would typically need more than a handful of lists so long as the logic behind each list was concrete and understandable, alongside a skilled and well executed segmentation strategy.


If your business is in the habit of maintaining or adding list after list, stop and ask yourself why and what you are trying to achieve from this practice. Once you understand and get to grips with the fundamental principles of effective data management and list hygiene, alongside clearly defined goals - then in the vast majority of cases, it becomes extremely clear on the benefits of consolidating all of your data down into one main master list.

If you found this article useful, follow me on Twitter and LinkedIn where I break down eCommerce email marketing strategies we use with our clients daily. Check out our newsletter too for more insider insights into email marketing.

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