29 - 12 - 2025

Server-Side Tracking for Klaviyo: Stop Losing Flow Revenue

Introduction

If you’re running abandoned cart and browse abandonment flows in Klaviyo, there’s a good chance a significant portion of your potential revenue is slipping through the cracks. Not because your email copy isn’t compelling or your timing is off, but because Klaviyo simply doesn’t know those customers exist. The culprit? Browser-based tracking limitations that have intensified dramatically over the past few years, leaving eCommerce brands with incomplete data and underperforming automations.

The numbers are stark. According to Polar Analytics, Klaviyo by itself can miss up to 60-70% of cart abandoners when visitors aren’t logged in or return after the cookie window expires. Elevar reports that standard browser-based tracking is often unable to recognise users past 24 hours in many cases. For Australian eCommerce brands, this problem is particularly acute: with iOS commanding around 54-60% of the mobile market locally compared to just 27% globally, a far greater proportion of your traffic is subject to Safari’s aggressive tracking restrictions. This represents a substantial revenue leak that most brands don’t even realise exists.

The solution lies in server-side tracking, a technology that bypasses the browser entirely to capture customer behaviour and feed it directly into your email platform. This approach has moved from a nice-to-have technical improvement to an essential component of any serious eCommerce email strategy. In this article, we’ll explore why Klaviyo’s native tracking falls short, how server-side tracking addresses these gaps, and the landscape of solutions available to Australian eCommerce brands looking to recover this lost revenue.

Key Takeaways

Cookie limitations are costing you sales: Safari’s Intelligent Tracking Prevention (ITP) limits cookies to 7 days, and iOS 17 can reduce this to just 24 hours for some tracking scenarios. With iOS holding 54-60% market share in Australia (double the global average), local eCommerce brands are disproportionately affected.
60-70% of abandoners may go untracked: When visitors aren’t logged in or return outside the cookie window, Klaviyo’s client-side tracking cannot identify them, so your abandonment flows never trigger.
Server-side tracking bypasses browser restrictions: By sending events directly from your server to Klaviyo, you can identify customers even when cookies fail, ad blockers intervene, or visitors switch devices.
Multiple platforms offer solutions: Elevar, Triple Whale, Littledata, Polar Analytics and others provide server-side tracking integrations for Klaviyo, each with different strengths and pricing models.
Implementation requires flow duplication: To measure incremental lift, most solutions recommend cloning your existing Klaviyo flows with server-side triggers rather than replacing them outright.
Results can be dramatic: Brands report anywhere from 14% to 300% increases in abandonment flow revenue after implementing server-side tracking, depending on their baseline tracking accuracy.

Why Standard Klaviyo Tracking Falls Short
What Server-Side Tracking Changes
The Server-Side Tracking Landscape
Implementation Considerations

Why Standard Klaviyo Tracking Falls Short

To understand the problem, you first need to understand how Klaviyo’s default tracking actually works. When you install Klaviyo on your Shopify store, it places JavaScript tracking code on your website that monitors visitor behaviour, including product views, cart additions and checkout starts. This client-side approach relies on cookies stored in the visitor’s browser to identify who’s doing what. When everything works as intended, a visitor adds something to their cart, Klaviyo recognises them from a previous email signup or purchase, and your abandoned cart flow triggers if they don’t complete the purchase.

The problem is that modern browsers, particularly Safari on Apple devices, have implemented aggressive privacy measures that fundamentally undermine this approach. Apple’s Intelligent Tracking Prevention (ITP) forces cookies set by JavaScript to expire after just seven days of Safari use without user interaction. With iOS 17 and Safari 17, these restrictions have become even more stringent, with some scenarios reducing cookie lifespans to as little as 24 hours.

For Australian eCommerce brands, this creates a particularly challenging environment. According to Red Search’s analysis of Australian mobile statistics, iOS holds between 54-60% of the mobile operating system market locally, peaking at 62% in 2023. This compares to a global iOS market share of just 27%. Meanwhile, Safari accounts for approximately 31% of all browser traffic in Australia. In practical terms, this means well over half of the mobile visitors to your Shopify store are browsing on devices with aggressive tracking restrictions built in. New Zealand tells a similar story, with iOS holding around 45-50% market share. The implication is clear: Australian and New Zealand eCommerce brands face a significantly larger tracking blind spot than their counterparts in markets where Android dominates.

The Compounding Effect of Ad Blockers

Cookie restrictions aren’t the only challenge. Research indicates that nearly half of global internet users now use some form of ad blocker, with 38.8% penetration in the United States alone. Many of these tools block tracking scripts from loading entirely, meaning Klaviyo’s JavaScript never fires in the first place. Even users who don’t actively install ad blockers may have tracking protection enabled by default in browsers like Firefox and Brave. The result is a growing segment of your traffic that exists in a data blind spot, browsing your products and abandoning carts without ever appearing in your Klaviyo metrics.

The Real-World Impact on Your Flows

Consider a typical customer journey that breaks under these conditions. A visitor clicks on your Meta ad, lands on your product page, and enters their email in your popup to receive a discount code. They browse a few more products but don’t purchase. Under Klaviyo’s client-side tracking, their browser now has a cookie linking their session to their email address. If they return within seven days and abandon their cart, Klaviyo can identify them and trigger your flow. But if they return on day eight, or if they’re using Safari with strict privacy settings, or if they clear their cookies, or if they switch from their phone to their laptop, that connection is broken. TrackBee notes that this scenario is increasingly common, with Klaviyo simply unable to recognise returning visitors and connect their activity to existing profiles.

What Server-Side Tracking Changes

Server-side tracking takes a fundamentally different approach to the problem. Instead of relying on JavaScript running in the visitor’s browser, server-side solutions capture events at the server level and send them directly to Klaviyo via API. This bypasses browser restrictions entirely, since the tracking happens on infrastructure you control rather than in an environment subject to ad blockers, cookie limitations and privacy features. The data flows from your Shopify store’s servers to Klaviyo’s servers without ever touching the browser’s tracking defences.

The key innovation that makes server-side tracking valuable for email marketing is something called session enrichment or identity resolution. These systems maintain their own database of visitor identities, using various signals to link anonymous browsing sessions to known email addresses. When a visitor who signed up for your newsletter six months ago returns to your site, a server-side tracking solution can often recognise them even when Klaviyo’s cookie has long since expired. Elevar’s documentation explains that their server-side tracking allows you to set a persistent cookie that can last up to a year, meaning customers returning weeks or even months later can still be identified and your abandonment flows will trigger as intended.

How This Translates to Revenue

The practical impact is straightforward: more identified visitors means more flow triggers, which means more revenue from your existing automations. Rather than your abandoned cart email going to the subset of customers who happened to be logged in or returned within the cookie window, it reaches a much larger audience of actual cart abandoners. The same applies to browse abandonment, checkout abandonment and active-on-site flows. Littledata reports that between 40% and 300% more abandoned cart emails can be triggered with proper server-side tracking, with a corresponding increase in purchases from these flows.

Enhanced Data Quality

Beyond simply identifying more customers, server-side tracking typically delivers richer event data to Klaviyo. Where client-side tracking might capture that a product was added to cart, server-side solutions often include the entire cart contents, detailed product attributes, and additional context that enables more sophisticated personalisation. This allows you to build flows that reference all items in the cart rather than just the last product added, or segment based on cart value thresholds with greater accuracy. The data quality improvement compounds the identification improvement to create a meaningfully better-performing email programme.

The Server-Side Tracking Landscape

Several platforms now offer server-side tracking solutions that integrate with Klaviyo, each with different approaches, pricing structures and feature sets. Understanding the landscape helps you make an informed decision about which solution might suit your brand’s needs and technical capabilities.

Elevar

Elevar has positioned itself as a comprehensive conversion tracking solution for Shopify brands, with Klaviyo integration as one of several destination platforms. Their Session Enrichment technology stitches together events, sessions and channel attribution data, recognising returning users and connecting their behaviour across visits in real-time. Elevar claims their customers consistently experience a 50% or greater increase in product view and add-to-cart events sent to Klaviyo, with some brands reporting a 200% increase in emails sent to customers who would otherwise have been untracked. Their Klaviyo marketplace listing cites potential flow revenue increases of 25% to 300% depending on the brand’s baseline tracking accuracy.

Triple Whale

Triple Whale approaches server-side tracking through their Sonar feature, which enriches customer data and sends events back to marketing platforms including Klaviyo. Their system sends pixel events to Klaviyo to capture browse and cart abandonments that standard tracking misses. A case study with Paw.com documented a 14.2% increase in incremental Klaviyo flow revenue within two months of implementing Sonar, with the brand’s Senior Marketing Director noting that their abandoned cart flow consistently outperformed their existing enrichment solution. Triple Whale’s broader positioning as an analytics and attribution platform means the Klaviyo integration is part of a larger data infrastructure play.

Littledata

Littledata pioneered server-side tracking for Shopify and offers deep integration with Klaviyo alongside Google Analytics, Meta Ads and other destinations. Their approach uses a PersistentID technology that maintains a server-side device graph to identify users beyond browser limitations. Littledata’s CEO has stated that their server-side tracking can double abandoned cart and abandoned browse flow revenue compared to Klaviyo’s native tracking. Their Added to Cart event includes the entire cart contents rather than just the last added product, enabling more sophisticated personalisation in abandonment flows.

Polar Analytics

Polar Analytics offers a Klaviyo Flows Enricher that uses their first-party Shopify App Pixel to track abandonment events that Klaviyo’s cookie-based tracking misses. They claim to capture up to 70% more abandonment events, generating a persistent identifier for each visitor that works even when browser cookies expire or are blocked. Their documentation includes case studies showing significant revenue increases from Browse and Cart Abandonment flows within weeks of implementation.

Implementation Considerations

Implementing server-side tracking for Klaviyo isn’t as simple as installing an app and watching revenue climb. There are technical and strategic considerations that affect how successfully you can capture the potential gains and how accurately you can measure them.

Flow Duplication Strategy

Most server-side tracking solutions recommend cloning your existing Klaviyo flows rather than replacing them. The cloned flows use server-side event triggers (such as “Added to Cart – Elevar SS” or “Viewed Product – Triple Whale”) instead of Klaviyo’s native events. This approach allows you to run both flows in parallel initially, measuring the incremental lift from server-side tracking while maintaining your baseline performance. You’ll need to configure flow filters carefully to prevent customers from receiving duplicate emails, typically by excluding anyone who has already received the equivalent flow triggered by native tracking. Klaviyo’s smart sending feature provides an additional safeguard, with a default 16-hour window that prevents sending multiple emails too quickly.

Measuring Incremental Value

Understanding the true impact of server-side tracking requires careful measurement. The emails sent and revenue earned from your server-side triggered flows represent the uplift from enhanced tracking, as these are customers who would not have been captured by Klaviyo’s native tracking alone. Most platforms provide dashboards or reports that show server-side tracked events alongside native events, allowing you to quantify the improvement. Be prepared for a ramp-up period as the identity resolution systems build their database of visitor profiles. Performance typically increases over time as returning users visit and their previously expired cookies are replenished with persistent identifiers.

Cost-Benefit Analysis

Server-side tracking solutions carry ongoing subscription costs that need to be weighed against the revenue they recover. Pricing models vary significantly, from flat monthly fees to percentage-of-revenue arrangements to tiered plans based on order volume. When evaluating ROI, consider not just the direct revenue from additional flow triggers but also the improved data quality for segmentation and the enhanced attribution accuracy for your broader marketing stack. Many solutions offer free trials or money-back guarantees, allowing you to validate performance before committing to ongoing costs.

Bringing It All Together

The shift toward privacy-first browsing has fundamentally changed the technical requirements for effective email marketing automation. What worked five years ago, relying on browser cookies to identify visitors and trigger flows, now leaves substantial revenue on the table as Safari’s ITP, ad blockers and cross-device browsing create growing blind spots in your customer data. For Australian eCommerce brands, this challenge is amplified by our market’s strong preference for Apple devices: with iOS commanding nearly 60% of mobile traffic locally, the tracking gap affects a far larger proportion of visitors than in markets where Android dominates.

The good news is that the technology has matured significantly, with multiple proven solutions available that integrate directly with Klaviyo and Shopify. Whether you prioritise comprehensive attribution (Elevar, Triple Whale), Klaviyo-specific optimisation (Littledata, Polar), or specialised abandoned cart recovery (wetracked.io, AImerce), there’s a solution suited to different technical capabilities and budget constraints. The key is understanding that this isn’t about replacing Klaviyo’s functionality but augmenting it with better data collection that allows your existing flows to perform as intended.

For brands currently seeing strong performance from abandonment flows, server-side tracking offers the opportunity to identify customers you’re currently missing and expand your addressable audience. For brands struggling with lower-than-expected flow revenue, the issue may not be your email strategy at all but rather a tracking problem that’s preventing flows from triggering in the first place. Either way, auditing your current tracking accuracy and understanding the gap between actual abandonment behaviour and triggered flows is the essential first step.

How The Orchard Agency Can Help

With over 16 years of experience helping brands harness the power of email marketing, The Orchard Agency has seen the evolution of tracking technology from simple cookie-based systems to today’s complex privacy-first landscape. As a Klaviyo partner, we understand both the platform’s native capabilities and its limitations, and we work with brands to implement solutions that maximise their email programme performance.

Our marketing automation team can audit your existing Klaviyo flows to identify tracking gaps, evaluate server-side tracking solutions suited to your technical environment and budget, and implement the integrations needed to capture the revenue you’re currently missing. We handle the technical complexity of flow duplication, trigger configuration and performance measurement so you can focus on strategy and creative.

Whether you’re looking to diagnose why your abandonment flows underperform benchmarks, implement server-side tracking to recover lost revenue, or optimise your broader email automation strategy, we’re here to help. Get in touch to discuss how we can elevate your Klaviyo performance.

Frequently Asked Questions

What is server-side tracking for email marketing?

Server-side tracking captures customer behaviour data at your website’s server level and sends it directly to platforms like Klaviyo via API, rather than relying on JavaScript code running in the visitor’s browser. This approach bypasses browser privacy restrictions, ad blockers and cookie limitations that prevent traditional client-side tracking from identifying returning visitors. The result is more complete data about who’s browsing, adding to cart and abandoning purchases on your site.

Will server-side tracking work with email platforms other than Klaviyo?

Most server-side tracking solutions support multiple destinations beyond Klaviyo, including platforms like ActiveCampaign, Omnisend and others. However, the specific integration depth and feature set varies by platform. Klaviyo tends to have the most mature integrations due to its popularity among Shopify brands, so if you’re using a different email platform, you’ll want to verify the specific capabilities available before committing to a solution.

How long does it take to see results from server-side tracking?

Most brands begin seeing incremental flow triggers within the first week of implementation, as the identity resolution systems start connecting anonymous sessions to known profiles. However, performance typically improves over subsequent weeks and months as the system builds a more comprehensive database of visitor identities. Elevar and others report that results continue to increase over time as returning users visit and their sessions are enriched with persistent identifiers.

Do I need technical expertise to implement server-side tracking?

The major server-side tracking solutions for Shopify are designed for relatively straightforward implementation, typically involving app installation and configuration rather than custom development. However, optimising the setup, configuring flow triggers correctly, setting up proper filters to prevent duplicate emails and measuring incremental performance does require familiarity with Klaviyo’s flow builder and event structure. Working with an agency experienced in both Klaviyo and server-side tracking can significantly accelerate time-to-value.

Is server-side tracking compliant with privacy regulations like GDPR?

Server-side tracking can actually improve privacy compliance compared to client-side approaches, since you have greater control over what data is collected and sent to third parties. Most solutions support consent management integration, allowing you to respect user preferences while still capturing permitted tracking data. However, you should still ensure your implementation aligns with your privacy policy and applicable regulations, particularly around how visitor identities are stored and matched.

Sources & Further Reading

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