Google is still preparing for the death of cookies, but now the company is offering a more in-depth look at how automation will take over where cookies left off in regard to targeting ads online.

On Tuesday, Google released a new paper about its post-cookie project, explaining how its programmatic ad platform, which is used by publishers and brands to automate online ad targeting, will work once cookies go away at the end of 2024. The plan is still to deprecate cookies—the technology that has underpinned programmatic ad targeting for decades—in favor of automated advertising techniques that are deemed safer for privacy.

“As third-party cookies are phased out, ad tech solutions for interest-based advertising should evolve to take advantage of privacy-friendly signals to show relevant ads. These include first-party data, contextual signals and platform-provided privacy-preserving APIs,” Google said in a statement.

The whole ad tech world is watching Google and its so-called “Privacy Sandbox” experiments, which will become the foundation of how ad tech platforms use Google technology to serve ads to millions of websites. Online publishers use Google Ad Manager to fill ad inventory when people visit their sites, and advertisers use Google’s demand-side platform to buy ads across the web.

The old ways of running those internet auctions are changing, since third-party cookies are falling out of favor. Apple was one of the main proponents over the years of blocking such cookies, which are files that are dropped on consumers’ web browsers to track people across the web. Cookies make it easy to peek into someone’s online habits and serve personalized ads, but privacy advocates have pushed tech platforms to rely less on tracking. Without cookies, publishers have less data to tell advertisers when their ads work, and brands have less data to refine their online marketing techniques.

Google has been slower to deprecate cookies, compared to Apple, because more of the advertising ecosystem relies on the company to run internet campaigns, and any changes to Google’s system has major implications, especially if any changes adversely affect internet rivals while benefitting Google. Apple has also come under scrutiny for changing how it shares data from Safari web browsers and iPhones in ways that have stifled ad revenue for major platform partners including Meta, Twitter and Snapchat.

Google started testing components of its "Privacy Sandbox" in 2021. The company has had to retool the program while it figures out how to conduct online ad auctions, and provide measurement to ad partners, without the use of cookies on web browsers. Google is also following Apple’s path by eliminating similar identifiers on mobile devices, making the mobile ad ecosystem less precise and less reliant on sharing-personal data. Google has had to delay the full deprecation of cookies a couple of times, and just reiterated that they will be phased out by the end of 2024.

Related: Google's cookie strategy splits the ad industry

Google’s privacy experimentation has been slow-going. It relies on new application programming interfaces—APIs—which publishers and ad tech companies plug into to help deliver and measure ad campaigns. The company has been testing similar tools to run ads on Chrome web browsers and Android devices. Google also has the Topics API, which shares limited browser-history data that publishers can then use to help fine-tune ad targets.

On Tuesday, Google explained the type of advertiser that would most benefit from the Topics API. Ad tech solutions can call the Topics API to get interests for a given user, while the API protects privacy by limiting the length of browsing history considered, the parties that can access a given topic, the number of categories being returned, and more. This API is particularly useful for ad tech that doesn’t have direct publisher relationships or contextual optimization capabilities, Google said.

Google also suggested the Topics API would be more useful for publishers that could pare that information with “contextual” data from their websites. Publishers know the type of stories and videos that visitors engage, and that could inform ad targeting when combined with the limited data from the Topics API, Google said.

Google also discussed the FLEDGE API, which is one of the new ways brands will be able to potentially retarget ads—meaning they find returning customers or people in the market for certain products—without relying on cookies. (FLEDGE stands for First Locally Executed Decisions Over Groups Experiment.) FLEDGE is considered more private because it keeps the personal data about what interest groups a person is in, or what products they are in market for, locally stored on the device, instead of sharing that information. Advertisers and their tech partners can create audience segments by labeling visitors to a web page as members of a particular segment, such as “interested in family adventures,” Google said. “If the ad tech solution provider has other websites in its partner network that pertain to ‘family adventures,’ they can also add visitors for those sites to this same segment.”

Google’s "Privacy Sandbox" success will depend a lot on how much adoption it spurs from companies that are sometimes rivals to Google. For instance, Amazon has been testing FLEDGE, according to a recent post on LinkedIn from Sincera's Ian Meyers detailing the company’s participation in early FLEDGE experiments. (Amazon was not immediately available for comment.) Other companies including Microsoft’s Xandr, Criteo and RTB House have been testing parts of Google’s "Privacy Sandbox," but it’s been slow so far.

Google’s update on Tuesday was mostly a rallying cry for potential partners to start using and testing the privacy tools. One of the criticisms of the program so far has been the limited amount of data that publishers and ad tech partners can glean from it while it’s still in its infancy. “Invest in integrating privacy-preserving APIs such as Topics, FLEDGE and Attribution Reporting into your ad tech solutions, to support common interest-based advertising use cases after third-party cookies go away,” Google said.