Third-party cookies have long been controversial, allowing ad companies to track users across websites without explicit consent.
For years, this went unnoticed, but then came the pushback: regulators tightened up, Apple set the tone with stricter privacy rules, and users started paying attention.
So Google had to move.
“The third-party cookies phaseout began in 2024, and even though it’s taking longer than expected, it continues in 2025. The change highlights the need for advertisers to adapt to a more privacy-conscious landscape and embrace new tools to balance effective targeting with user trust,” says Nalini Prasad of blusharkdigital.com. If your ads ever depended on this old system, now’s the time to understand what’s changing, why it matters, and what you can still do.
How We Got Here
To understand where we are now, you must know the difference between first-party and third-party cookies.
First-party cookies are the ones you expect. They are set by the website you’re visiting to make your experience smoother. They keep your session active, remember your preferences, and make the site usable.
But third-party cookies? These are from outsiders. Usually embedded on the page through ads, social buttons, or tracking scripts, they follow you across the web and stitch together a version of “you” for advertisers to bid on.
That surveillance model became the fuel for digital advertising. Companies could target you based on your behavior across dozens of sites, not just the one you were on. But there was a serious flaw: users never opted in. And most didn’t even know it was happening.
Even worse, entire businesses have popped up around buying and selling this data, profiting from people’s browsing histories without their knowledge or consent.
It was not until the late 2010s that the tide shifted. Privacy regulations gained teeth. The General Data Protection Regulation (GDPR) came first, making consent a legal requirement in Europe. The California Consumer Privacy Act (CCPA) followed in California. Then, Apple took a strong stand with Intelligent Tracking Prevention in 2017, setting new expectations around user privacy.
It took Google a while to act. But by 2020, the writing was on the wall. After multiple delays, Google began its official phaseout in 2024, with the process now deep into rollout across 2025.
Google’s New Tools for Advertisers
Google was never going to just unplug third-party cookies and call it a day. Its entire business runs on advertising, so walking away from that model wasn’t an option.
What it needed was a way to keep ad dollars flowing without spooking users or regulators. That’s where the Privacy Sandbox comes in. It’s not one tool, but a bundle of APIs that let advertisers still reach audiences in a targeted way, just without tracking people individually across sites.
Here are the core APIs in the new Privacy Sandbox:
Protected Audience API (formerly FLEDGE)
The Protected Audience API gives advertisers a way to keep retargeting without triggering privacy alarms. Traditionally, retargeting worked because the trackers followed you around like a shadow. Now, that shadow lives inside your browser. Chrome saves a note that says “this person visited that store.” When ad space opens up elsewhere, it can show a relevant ad based on that note, without sending the data anywhere else.
Topics API
Instead of tracking your every move, it puts you into broad interest categories based on the types of sites you’ve visited recently. Things like tech, travel, or fitness. Chrome stores those topics locally, picks a few each week, and lets advertisers ask something like, “Is this person into gadgets?” If that fits, an ad can be shown. But the key thing here is that your online browsing history stays private. There’s no master file, no identity. Just a few high-level hints shared in a way that’s less invasive but still useful for targeting.
Attribution Reporting API
At some point, every advertiser needs to answer one basic question: Did the ad work? That’s where the Attribution Reporting API comes in. It’s Google’s replacement for detailed conversion tracking cookies. But it doesn’t tie conversions back to individuals. Instead, it sends aggregated or delayed data, helping you understand performance in broader strokes.
Final Words
The end of third-party cookies marks a pivotal shift in digital advertising, pushing advertisers to adapt to a more privacy-conscious landscape. With tools like Google’s Privacy Sandbox, the industry is finding ways to balance effective targeting with user trust. While the transition may be challenging, it presents an opportunity to build a more transparent and ethical advertising ecosystem, one that respects user privacy while still delivering meaningful results.
