In 2002, Terziev founded the software company
Telerik together with Svetozar Georgiev, Boyko Yaramov and Hristo Kosev, and was its CEO for several years. In its early months, Telerik was involved in website development, but soon moved towards creating its own software products and components. As sales grew in the US market, Telerik attracted the attention of investment firm
Summit Partners, which invested in the company in 2008 and helped improve its management. Telerik's business grew rapidly, including through acquisitions in
Europe and
North America, and in 2013 had 800 employees and 15 offices in various countries around the world. In 2009,
Telerik established Telerik Academy, a center for specialized training of software professionals, which in the following years played an important role for the software sector in Bulgaria. Terziev was a co-founder of the academy. After several years of rapid sales growth of about 20% per year, in October 2014 the founders of Telerik sold the company to the American software company
Progress Software, with an announced value of $262.5 million. That was the largest deal in the Bulgarian technology business as of 2014. == Political career ==