An ad server is a software platform that allows companies to manage, serve, and track their online advertising campaigns. It is used to deliver advertisements to websites and track the performance of those ads. Ad servers provide a range of features, such as the ability to target specific audiences, manage creative assets, and track performance metrics. They are also used to manage campaigns across multiple channels, such as display, video, and mobile. Ad servers are an essential part of the digital advertising ecosystem, as they enable advertisers to efficiently manage their campaigns and measure their success. By providing detailed analytics, ad servers help advertisers understand which campaigns are working and which need to be adjusted or replaced. Ad servers also provide publishers with the ability to monetize their websites and apps, as they can serve ads from multiple advertisers. Ultimately, ad servers help advertisers and publishers maximize their return on investment.