Source From Allowed vendors via the DoubleClick Ad Exchange The following approved vendors are certified to serve 3rd-party ads on the DoubleClick Ad Exchange platform in all regions unless otherwise noted below. Please note which vendor is allowed as a 3rd- or 4th-party call. The certified vendors permitted to make 3rd-party calls are generally of the following type: Demand Side Platform, Agency Trading Desk, Ad Network, Ad Exchange, Standard Ad Server & Rich Media Vendors. The certified vendors permitted to make 4th-party calls are generally of the following type: Research products, which include Analytics/Performance, Brand-Lift Studies, & Verification Services. Learn more about Vendor and technology definitions .