If you run an ecommerce store on Shopify, chances are you started with Klaviyo: it comes recommended by default, integrates with no friction, and handles abandoned cart and the weekly newsletter well. Klaviyo does not fail there. It fails once automation needs data that is not born in the order, and at that point the problem is not the tool: it is the underlying data model.
Klaviyo automates one thing well
Klaviyo builds its flows on top of the events Shopify already generates: product viewed, checkout started, order placed, product repurchased. As long as automation stays inside that event set, it works fast and with no friction: catalog, inventory, and purchase history are already there, with no extra integration. That is why it is, rightly, the default path for a small or mid-size Shopify store.
Where it starts to fall short
The limit shows up once the business wants to automate something that did not happen at checkout: a WhatsApp reply, a support ticket, an in-store sale, an event that lives in another system. Klaviyo assumes the store is the only source of truth. Customer.io starts from a different place: it builds one profile per customer that can take in events from any system, not only Shopify, so it does not care where the data comes from.
Three signs a business has already crossed that line:
- More than one channel runs its own rules (support, WhatsApp, in-store sales) that do not talk to each other.
- The same segment gets built by hand in more than one tool because none of them holds the full set of customer events.
- A real automation needs data that today lives in a spreadsheet or a separate system, not in the order.
None of the three is a Klaviyo problem: they are a sign the business has outgrown the single-tool, store-only model. It is the same diagnosis we make in what is a CDP: having the tool installed is not the same as having it running on complete data.
To simplify that jump on Shopify, we built an app that integrates Customer.io in three steps, with no store rewrite: Customer.io Tracker on the Shopify App Store. It is also the work we do with ecommerce brands in the United States: before adding a new tool, confirm whether the real limit is a channel problem or a data problem.
If your team builds the same segment twice because no single tool holds every customer event, that is probably no longer a Klaviyo problem.