[3] He graduated from the First English Language School, after which he obtained a Business Administration degree from the American University in Bulgaria.

[4] In 2002, Terziev founded the software company Telerik together with Svetozar Georgiev, Boyko Yaramov and Hristo Kosev,[5] 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.

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.

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.