If you run an ecommerce business in the UK and you are still using Mailchimp because you started with it years ago, you owe it to yourself to look at this properly. Mailchimp is a fine email platform for general use. But for ecommerce specifically, the gap between Mailchimp and Klaviyo has widened to the point where staying on Mailchimp is costing you money.

The core difference

Mailchimp was built as a general-purpose email marketing platform. It works for newsletters, announcements, and basic automations across any type of business. Klaviyo was built specifically for ecommerce. Every feature, every integration, every piece of analytics is designed around the reality of selling products online. That focus makes a meaningful difference.

Segmentation

This is where Klaviyo pulls furthest ahead. Klaviyo integrates directly with Shopify, WooCommerce, and other ecommerce platforms to pull in real-time purchase data, browsing behaviour, and customer lifetime value. You can segment your list based on what people actually bought, how much they spent, how recently they purchased, and what products they looked at but did not buy.

Mailchimp has improved its ecommerce segmentation, but it still treats purchase data as one data source among many rather than the central organising principle. The segments you can build in Klaviyo are more granular, more powerful, and more directly tied to revenue.

Automations

Klaviyo's pre-built ecommerce automations are genuinely good. Abandoned cart flows, post-purchase sequences, win-back campaigns, browse abandonment, price drop alerts — they all come with sensible defaults that you can customise. More importantly, these flows can use the deep segmentation data to personalise at a level Mailchimp cannot match.

Mailchimp has automations too, and they have improved significantly. But the ecommerce-specific flows are less sophisticated. The abandoned cart email works, but the ability to personalise based on cart value, product category, or customer history is more limited.

Integrations

For Shopify specifically, Klaviyo's integration is best-in-class. The data sync is real-time, the setup is straightforward, and the depth of data available inside Klaviyo is impressive. Mailchimp's Shopify integration works but has had a rocky history — they were removed from the Shopify app store in 2019 and only returned later with a rebuilt integration.

For WooCommerce, both platforms integrate well. Klaviyo still has the edge in data depth, but the gap is smaller.

Pricing

Mailchimp is cheaper at every list size. That is a fact. For a list of 10,000 contacts, Mailchimp's Standard plan costs roughly half of what Klaviyo charges. For small businesses watching every pound, that difference matters.

However, pricing needs to be measured against revenue generated, not just cost. If Klaviyo's better segmentation and automation generates even a small percentage more revenue from your email channel, the extra cost pays for itself several times over. For ecommerce businesses doing serious volume, the ROI case for Klaviyo is strong.

The honest verdict

If you are an ecommerce business on Shopify doing more than five thousand pounds per month in revenue, Klaviyo is the better choice. The segmentation, automations, and Shopify integration are meaningfully better and will directly impact your email revenue.

If you are a small ecommerce business just starting out and your list is under a thousand contacts, Mailchimp's free tier or basic plan is a reasonable starting point. Switch to Klaviyo when your revenue justifies the cost.

If you are not an ecommerce business, Mailchimp is probably the better option. Klaviyo's strengths are specifically tied to ecommerce data. Without that data, you are paying more for features you will not fully use.

At Brilliant, we have migrated several UK ecommerce clients from Mailchimp to Klaviyo. The typical result is a thirty to fifty percent increase in email-attributed revenue within the first three months, mostly from better abandoned cart flows and smarter segmentation. If you want to know whether the switch makes sense for your business, book a call and we will look at your numbers.