Konstantinos is COO of YESTAY, the first company in Greece to cover the full spectrum of flexible living, from a single night to long-term housing, with more than 800 properties under management. Ten years ago he founded UPSTREET in Athens and grew it into one of the city’s best-known vacation rental brands. In 2026 UPSTREET joined YESTAY, and he now leads operations across the company. A civil engineer with more than 20 years in real estate, Konstantinos knows the Athens market from the ground up: which neighbourhoods are in demand, what makes a property perform, and how to serve owners at every stage.