He never finished his studies in architecture but secured a permit to run a building practice in 1902.
Vanags designed a number of churches in Riga and approximately 70 multi-storey apartment buildings in the city before World War I, most of which are in a National romantic style of Art Nouveau architecture.
During World War I, he worked for the road construction department of the Imperial Russian army but during the German occupation of Riga he helped organise an exhibition in Berlin about Latvian art (in 1918).
He returned to Riga in 1919 and worked with the building department of the city during the Communist occupation.
He was a victim of the so called Red Terror because he was arrested and executed by firing squad for "counterrevolutionary activities".