Amazon Ad Server

Was a major third-party ad server alternative to Google Campaign Manager 360, operating as part of Amazon's advertising technology portfolio before being shut down in 2024.

Amazon Ad Server, formerly known as Sizmek, was an enterprise-grade ad serving and creative management platform operated by Amazon following its acquisition of Sizmek's ad server and dynamic creative optimization (DCO) assets in 2019. The platform enabled advertisers and agencies to manage, deliver, and measure advertising campaigns across multiple channels, offering capabilities such as ad trafficking, creative versioning, cross-channel measurement, and rich media support. It served as a significant alternative to Google's Campaign Manager 360 in the third-party ad server space. Amazon rebranded the Sizmek Ad Suite as Amazon Ad Server and positioned it as part of its broader advertising technology ecosystem, which includes the Amazon DSP and Amazon Marketing Cloud. The platform attracted large agencies and enterprise advertisers seeking an independent ad server not tied to Google's stack. However, Amazon struggled to grow the product competitively, and the platform never fully captured the market share needed to challenge Google's dominance in ad serving. In late 2023, Amazon announced it would sunset Amazon Ad Server by the end of 2024, effectively exiting the third-party ad server business. Amazon pointed customers toward alternatives such as Flashtalking and Smartly as migration paths. The shutdown marked a significant moment in the AdTech industry, reinforcing Google's near-monopoly position in the ad serving market and raising further questions about competition in digital advertising infrastructure.