This is the latest in a series of hires, as iProspect continues to grow with a focus on driving digital performance for its clients.
Soeder brings experience across a range of brands and sectors, including financial services, retail and travel.
She joined Moneysupermarket in 2007, where she was responsible for project-managing the launch of the brand’s website in Germany, and, most recently, led the performance specialist Greenlight.
Matt Adams, chief media officer at iProspect UK, said: "Britt has built, grown and led performance businesses throughout her career. She will make a huge impact in one of our fastest-growing service areas."