Purplebricks is the most well-known online estate agent in the UK, and accordingly is the online agent with the largest market share, which is estimated at above 60% amongst all online estate agents, and 10% amongst all estate agents.
Purplebricks was founded in 2012, although officially launched in 2014, by brothers Kenny and Michael Bruce (whom you may recognise as the amusing duo starring in many of their pervasive adverts) has backing from several significant equity investors, including Neil Woodford, of Woodford Investment Management and has pushed itself to the front of the pack on the back of major marketing efforts.
It has since tried to expand to the USA and Australia, but these efforts have been met with mixed success.
Purplebricks actually operates as a hybrid agent, offering many services and 'local experts' that you wouldn't necessarily expect from an online estate agent.
As the UK's most prominent online agent, they are often regarded as a safe choice, however Purplebricks is not necessarily the best for those looking to maximise their savings.
Also note that Purplebricks' fee in London and surrounding areas is different. Instead of the usual offer of £899, the fee in London is £1,399.