Jack Dorsey's payments company Square is launching in the UK to kick off European expansion plans.
It's the fifth market for the New York Stock Exchange-listed tech company and the first in Europe after the US, Canada, Japan and Australia.
Square's launch here has been anticipated since last year, when it was first revealed it was setting up a UK company and gained authorisation from the financial regulator.
Several UK businesses across the country and different sectors have for some time been beta testing the device, which lets small merchants accept card payments, and its other suite of payments support options for small business such as online invoicing.
The company faces competition from the already established iZettle in the UK and Canadian firm Shopify which launched in the UK market last year.
But Dorsey suggested there was still plenty of room for Square.
"When we went to Japan we also faced a market which already had competitors in the market weren't the first and we didn't need to be first, we just need to be best," he said. "Best for us is fastest, simplest and most secure."
He added: "There are over 5m small businesses in the UK and half of thm are still not accepting credit cards. It's really a choice of participating in that economy or not," he said, providing "huge opportunity" and not just those switching from another company.
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"The most apparent differentiation [of Square] is giving access to funds the next business day." This allows companies to hire new people or spend money on marketing, he said, essentially investing in growing the business.
As for Europe, he noted that regulation would make expansion more challenging than for other startups. "Unlike many other startups, going into other markets is fairly heavy for us because we have to have a relationship with the bank and pay attention to the local regulation and every regulatory environment is different," he said.
"We're looking at our next markets, but we want to make sure that markets we're in are thriving first and foremost."