LONDON — For many European start-ups, making it big in the United States remains the pinnacle of success.
Not only does the United States still dominate the technology industry, but also many of the most coveted tech investors are on the West Coast, so having a presence there is at the top of many fledgling tech companies’ to-do lists.
Yet how do start-ups from places like Barcelona and Budapest crack the American market if local rivals have already set up shop?
Many companies take a shotgun approach, aiming at the whole United States at once and hoping to land paying clients more by luck than by a coherent strategy. But two London-based start-ups are taking a page right out of the playbook of companies like Uber by picking off individual cities one by one.
YPlan, a smartphone application that helps people find events, and Citymapper, a public-transportation app, are focusing on cities like New York and San Francisco.
On Tuesday, YPlan, which was started by two Lithuanian friends in London two years ago, announced that its app was also available in Las Vegas. That adds to its existing offerings in San Francisco, New York and London, and the company expects to introduce a version for Los Angeles by the end of June.
“You have to take things city by city, not country by country,” said Rytis Vitkauskas, one of the co-founders of YPlan at the company’s headquarters in central London. “To succeed in the U.S., you have to focus on what people want in their local markets.”
Mr. Vitkauskas and his fellow co-founder, Viktoras Jucikas, came up with their business idea while sitting in San Francisco after quitting their jobs for major finance firms in late 2011. The two had met on a basketball court while studying in Germany.
In San Francisco, the two wondered how they could find events like concerts and theater productions happening that night.
The original idea led them in 2012 to release a smartphone app for London that connected promoters and venues with people looking for something to do, with the start-up taking a cut of every ticket sold for each event. YPlan made its first foray into the United States with a New York-based version in late 2013.
“It has to be relevant for customers in each city that we enter,” said Mr. Vitkauskas, who now splits his time between London and New York and has hired a team in the United States to tweak the company’s product for each new market. “In two years’ time, we want to be in 20 to 40 cities.”
A focus on what matters to local consumers also has helped Citymapper move beyond its London roots.
When Azmat Yusuf moved to the British capital after finishing his M.B.A., he could not figure out London’s complicated public-transportation network, particularly the hundreds of bus routes.
In late 2011, London’s public-transportation authority opened up data about the city’s transport system to third-party developers. That allowed Mr. Yusuf to launch a smartphone app in 2012 that not only offered different travel suggestions from getting from point A to point B but also gave real-time transit information on London’s subway, bus and train network.
“As a megacity, London has been ahead of everyone at opening up its data,” said Mr. Yusuf, who was born in Pakistan and has worked at Google and the World Bank. “A lot of other cities are now following that example.”
Competing with other mapping services like Google Maps, Citymapper has been released in several other cities, including New York and — more recently — Boston and Washington. In Europe, the application is available in London, Paris and Berlin.
In New York, Citymapper gives users different options, including subway and bus-only routes, to get around the city. Last year, Citymapper won the Metropolitan Transportation Authority’s App Quest competition.
“We paid attention to the details that people wanted in each city,” said Mr. Yusuf, who said he took lessons from London’s bike-share system and applied them to others, including Citi Bike in New York. “For New Yorkers and Parisians, we knew we had to impress them.”
The Citymapper founder says that the London start-up is still looking at expanding into other markets like Hong Kong and Singapore.
But cities in the United States, particularly those with large populations that rely on public transportation, remain a priority.
“It’s also where the attention is,” Mr. Yusuf said.
An earlier version of this article erroneously included one city where Citymapper is active. While it serves the United States cities of New York, Boston and Washington, it is not active in San Francisco.