Illustration: Tiffany Herring/AxiosAppsFlyer has raised more than $1 billion in Series E funding at a $2.7 billion post-money valuation, Axios has learned from sources familiar with the financing.Why it matters: The investment is from four of the world's top advertising platforms, which are betting on the need for independent measurement as AI reshapes digital advertising.Driving the news: Moloco, Google, Meta and Unity have each acquired a minority stake in AppsFlyer, CEO and co-founder Oren Kaniel tells Axios. Kaniel did not comment on specifics of the deal."They believe what we believe: that attribution and measurement must be independent, unbiased and trusted," Kaniel says. "As AI takes over more of how advertising gets bought and optimized, the signals feeding those systems become the most consequential infrastructure in the industry."The investments are non-exclusive and while each company is integrated with AppsFlyer, they will not receive preferential treatment, he says.The transaction is subject to regulatory approvals.Context: AppsFlyer provides omnichannel measurement across mobile, the web and connected TV along with deep linking and data collaboration. The marketing tech company was founded in 2011.The SF-based company works with more than 15,000 brands globally and has about 1,300 employees.The company has previously raised $300 million. Its General Atlantic-led 2020 Series D was $210 million at a $1.6 billion post-money valuation, Kaniel says.Existing investors include Magma, Pitango, Eight Roads, Goldman Sachs Growth Equity, Qumra Capital, DTCP, Salesforce Ventures and General Atlantic.What's next: Kaniel says the investment will help the business move faster on improving omnichannel measurement and building agentic workflows. AppsFlyer also intends to go public."This is a milestone, not a destination," Kaniel says. "We have always believed AppsFlyer should one day stand as a public company, and this investment is a step on that path."Behind the scenes: Goldman Sachs served as exclusive financial advisor and Meitar Law Offices and Latham & Watkins as legal advisors to AppsFlyer.JPMorgan served as financial advisor and Freshfields and Herzog Law as legal advisors to Moloco. Fenwick served as corporate legal advisor to Meta. H-F & Co. served as legal advisor to existing investors.