60,000 customers across Europe have used the platform to invest in savings products outside of their own countries.

Raisin team Raisin's cofounders. Raisin

German fintech Raisin has passed €2 billion (£1.7 billion, $2.1 billion) of investment over its platform three years after launching.

Raisin announced in a press release on Tuesday that it had passed the milestone, just three months after announcing €1.7 billion had been invested over its platform. The fintech said the money comes from 60,00 customers, up from 50,000 in September.

Raisin's head of Europe Katharina Lueth told Business Insider: "Most customers start with one product to try out the platform but once they have seen that everything works they tend to come back for a second and a third product. The growth comes from both existing customers and new customers."

Berlin-based Raisin, founded in 2013, lets customers across Europe invest in savings accounts around the EU that offer the best interest rates. It claims its customers have earned €20 million in interest since its launch and German customers have earned €15 million more than they would have done had they invested in domestic savings products.

Raisin, formerly known as WeltSparen, does not hold customer money and instead opens an individual account for each saver with the corresponding account. Raisin currently has a German, English, Spanish, and French-language version of its service.

Lueth says expanding its network of local language websites and signing up new partner banks will be a priority for Raisin this year.

She told BI: "On our German platform its 27 partner banks now. One key area is to keep adding new partners to make sure we stay ahead of the curve and always have attractive products for our customers.

"We will continue to add more additional localised platforms for specific markets and we're also discussing distribution partnerships with banks and other fintechs."

She added: "The next billion is always faster than the previous one. The first billion took us two years and a couple of months, the second billion was a bit more than 6 months. I would expect us to add the third billion in the first half of this year for sure"

Raisin raised €20 million (£16.1 million) in August 2015. The funding round was led by Palo Alto-based Ribbit Capital and London's Index Ventures.