There are at least 25 alternatives to third-party cookies—but which is best?

With a focus on succeeding across three core pillars of digital marketing, these alternatives have been explored in the hopes of establishing the most stable, easy to input and reliable post-cookie solutions out there.

There are at least 25 alternatives to third-party cookies—but which is best?

Much has been said about how brands are under-prepared for the demise of the relatively simple technology that has been the bedrock upon which extraordinary growth in digital marketing has laid— the third-party cookie.

Whilst the majority of the post-third-party cookie debate has been dominated by controversy surrounding Google’s Privacy Sandbox's upcoming arrival and uncertainty about the exact date for the full third-party cookie deprecation on Chrome, where should marketers’ focus really be?

The Sandbox will inevitably play an important role in what happens next, yet there are at least 25 alternatives that are more or less ready to pick up where the third-party cookie leaves off.

However, the reality is that there is no single alternative (yet) that does everything the third-party cookie can do. The relative complexity that marketers are now faced with could well lead to mistakes and wasted budgets. But there is a solution: creating a structured plan to ensure digital marketing investment remains accurate and measurable.

For marketers still scratching their heads, Kepler has carried out an audit of established and emerging alternatives to third-party cookies. While these will continue to evolve as new changes come into play this year and beyond, we hope this will set you off on the right foot as you start to navigate the privacy-first marketing era.

Planning for complexity

Our first step was to categorise the third-party cookie alternatives based on the three core pillars of a digital marketing strategy:

Infrastructurewithin this category sits technologies that enable brands to collect and store audience data from the web, mobile app & offline environments, with consent being a vital component, specifically in the EEA/ UK.

Activationsystems that replace the third-party cookies’ ability to target ads to personalised audiences.

Measurement—There is nothing more important than measuring the effectiveness of an ad campaign, even if you have strong infrastructure/activation in place.

We then sought to rank alternatives based on their difficulty of use, their effectiveness as alternatives to third-party cookies, and the maturity of the technology.

Difficulty rating – ranging from ‘requires a high level of time and technical resource’ to ‘easily enabled within a short period’.

Cookieless grade—here, we ranked solutions from' a future-proof solution to a cookieless future’ to ‘those that do not bring any value’.

Maturity – grading from ‘fully built, stable and well-adopted’ to ‘highly speculative, in beta or development only’.

So, what did we find?

Infrastructure solutions

Contenders: First-party Party Data Management, Authenticated Data, Server-Side Tagging, First-Party Web Analytics, Clicks, and First-Party Cookies.

Winners: First-party data Management systems, Authenticated Data (data tied to known consented user identifiers), and Server-Side Tagging all get top ranking as third-party cookie alternatives. However, all three rank relatively complex in terms of difficulty, requiring a significant commitment from various stakeholders and technical expertise.

There is also a misconception that server-side tagging magically solves third-party cookie deprecation. This is false, mainly when there is a lack of first-party data to work with. The other alternatives, Clicks and First-Party Cookies (easy to do) and First-Party Web Analytics (very hard to execute), didn’t rank as complete third-party cookie alternatives.

Perhaps there are no surprises here, but given that not every brand has sufficient data to make first-party data work, this suggests brands should explore parallel solutions.

Activation solutions

Contenders: Contextual Targeting; Owned and Operated Audiences; Customer Match Lists; Publisher Deals; Curated Supply and Cohorts; Universal IDs; Google Topics API; IAB Seller-Defined Audiences; Google’s Protected Audiences API (PAAPI),

Winners: Contextual Targetingeasy to do and relatively mature; Owned and Operated Audiences (segmented at scale using proprietary first-party data from the tech platforms) – also easy to do and mature; Customer Match Lists (using brand data against publisher user information) – more challenging to do but mature; and Google’s Protected Audiences API (PAAPI), part of the Privacy Sandbox previously called FLEDGE which moves the ad auction decisions from ad server to browser, all ranked highly in the cookieless grading, although the latter still ranks low on maturity due to the sheer complexity of how it plans to work.

Whilst a contextual strategy is great for targeting, it only solves measurement beyond vanity metrics. Building Publisher Deals through private marketplaces/auction packages delivers accurate targeting, is easy to employ and is strong on maturity. Publisher data is inadvertently more attractive to advertisers than ever before.

We ranked both Google Topics API and the IAB Seller-Defined Audiences approach, which uses publisher-defined attributes within an Open RTB system, needing more maturity. The same applies to Universal IDs as a problematic, partial replacement lacking addressability/scale, particularly outside the US.

Measurement solutions

Contenders: Modelled Conversions; Data Clean Rooms; Lift Testing; Matched Markets and Geographical Lift; Google Regression-Based Attribution; Media Mix Modelling (MMM); Meta Robyn MMM; Surveys; Apple Private-Click Measurement; Google Attribution-reporting API; Meta and Mozilla Privacy Attribution.

Winners: Modelled Conversions, which can use predictive machine learning technology to measure conversions probabilistically, emerged as a leading alternative. It should be noted that this is only as useful as the inputted data, alongside the transparency of the modelling.

Google Regression-Based Attribution provides a middle ground between Marketing Mix Modelling (MMM) and in-platform attribution to speed up campaign reporting and optimisation. Two more aggregated forms of measurement, Lift Testing and MMM, are more critical than ever to have in place, no matter the size of your business.

Meta’s Robyn MMM approach showcases an open-source, low-cost alternative to MMM, although it may have further to go on difficulty and maturity, with a particular skill set required to build this up from scratch.


When measuring advertising on the web, brands need to accept that they should run multiple systems to maximise understanding of media investment performance. The idea of a single source of deterministic truth or multi-touch attribution tool is a fallacy. Avoiding the CFO’s ire

Of course, this is a snapshot as things will inevitably change. Some tech will improve, others might not, and new alternatives will arrive. However, it is imperative to understand the noise from the facts across these three pillars to know what set of solutions will at least provide some opportunity beyond a third-party cookie world.

There are use cases that will more than likely disappear without third-party cookies, and the ongoing discussion of the Privacy Sandbox’s proposals shows where these gaps are in the Google world. But ultimately, some of this is for the best in a privacy-centric space.

Apart from not having to admit to the CFO, “I know half of my advertising works, but not which half”, establishing a post-third-party cookie framework will reveal insights and ideas that perhaps the legacy approach couldn’t. And, after all, in the long term, an industry built around protecting consumer privacy is undoubtedly far better than one that tracks individuals however anonymously.

Jonathan D‘Souza-Rauto is the Biddable Product Lead at Kepler.

Performance Marketing World

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