Tributes poured in on Monday for the visionary co-founder of the Russian search engine Yandex, Ilya Segalovich, who died over the weekend of cancer aged 48.
Along with his former classmate Arkady Volozh, Segalovich turned Yandex into Russia's most popular search engine and a company valued at $10 billion on the New York stock exchange.
"I do not know how his encyclopaedic knowledge of technologies and his pure vision for the product can be replaced," said Volozh as he confirmed his co-founder's death.
"He leaves behind him a new generation and new school of IT experts," Volozh added.
Segalovich, who died in hospital in London, transformed the company from an Internet pioneer into a household name in Russia where it has 60 percent of the market and earns comparisons with Google.
"Ilya was a magician, a perfectionist," said top Yandex executive Anton Zabannykh.
Segalovich was in charge of the group's technological development and presided over launches that have allowed Yandex's continual growth, including popular mobile applications launched in 2012.
In May 2012, Yandex enjoyed a successful IPO on the Nasdaq exchange in New York.
Russian protest leader and popular blogger Alexei Navalny also paid tribute to a man sympathetic to the opposition who he said would remain "an example of ethics" in business.
"He was an ideal capitalist. He earned money with his head and hard work, was personally involved in charitable work and was not scared of supporting political projects," said Navalny, one of the first political figures in Russia to understand the power of the Internet.
Colleagues and rivals from the IT Russian world also paid tribute to Segalovich, who dreamt up his firm's catchy name from the English phrase "Yet another index".
Segalovich was a "unique engineer and a creator of world-class technology which is an outstanding example in the history of modern Russia," said the fonder of mail provider mail.ru, Yuri Milner, quoted by Vedomosti.
The founder of Russian social network VKontakte, Pavel Durov, said Segalovich's death was a "great loss", saying he was "one of the brightest people in Russian IT".