In the mid-90s, his family moved to Spain; Andreev himself relocated in 1995, but went back and forth between Spain and Russia.

In 1995, Andreev started his first business in Russia – an online store that sold computers and computer accessories via Internet. He sold Virus in 1997 for an undisclosed amount.

In 1999, Andreev founded SpyLog, a web-tracking business which helped webmasters track visits to their sites, as well as track users’ habits on the web. Although there were already existing services from Rambler and Mail.ru, SpyLog grew quickly.

In 2002, Andreev started contextual advertising firm Begun, often described as an earlier version of Google AdWords. A majority share of the company was purchased by Russian investment firm FINAM in 2004. Google tried to purchase Begun for $140 million in 2008.

Mamba was founded in 2004. Today it is the most popular dating site in Russia, with roughly 8 million users (or 13% of Russia’s Internet population) using its service. A majority share was sold in 2006 to FINAM and Mail.ru.

Andreev launched Badoo in 2006, with the product quickly spreading in popularity throughout Europe and into Latin America. Today it is the largest social network in the world for meeting new people, with over 360 million registered users, generating over $150 million per year and operating in 190 countries. In an article in 2011, Wired described Badoo as a ‘mass phenomenon’ in Brazil, Mexico, France, Spain and Italy.

In 2014, Andreev connected with previous Tinder co-founder Whitney Wolfe. After he persuaded her to move back into the dating space, together they built Bumble, the women-focused dating app. Speaking to The Guardian, Wolfe named Andreev as her biggest mentor in business. she also admits that Andreev “took the chance on her when no one else would”, and that “without him, the bumble journey wouldn’t have been possible”.

Andreev has spoken of his unique management style and the company culture at Badoo. In an interview in October 2017, he told Shortlist magazine that his philosophy in work is ‘to make people happy’, before discussing the food, perks and parties that are provided for Badoo’s staff. The company has since been named one of the Top 20 UK companies to work in, by Glassdoor.

In 2018, Andreev was named on Forbes’ global list of billionaires for the first time. As of September 2019, his net worth is estimated at $1.5 billion.

In 2019, Andreev launched MagicLab, a holding company that builds and owns dating and social networking apps Badoo, Bumble, Lumen, and Chappy in partnership with their founders. In November he sold his shares to Blackstone Group, the largest alternative investment firm in the world, which became a majority owner of MagicLab.