The app will allow users across the U.S. to buy and sell more than 50 crypto tokens from their mobile phones

Less than two months after Coinbase’s stock market debut, rival crypto exchange Kraken is bringing its mobile app to the U.S. as retail investors flock to digital currencies.

Starting Wednesday, the new Kraken App will allow many users across the U.S. to securely buy and sell more than 50 crypto tokens from their mobile phones.

This consumer app is our first major foray into supporting wider consumer adoption in a much more simplified, easy-to-use interface, Chief Product Officer Jeremy Welch told CNBC. The app launched in Europe earlier this year.

In terms of trading volume, Kraken is the world’s fourth-largest digital currency exchange.

In a crowded field of cryptocurrency apps, Kraken claims to offer the lowest fees in the industry. It points to its speedy verification and onboarding times as a key benefit. The fastest onboarding and purchase test is under a minute, depending on the user’s bank.

Outside the U.S., Kraken is popular because of its margin and futures trading offerings, which are not yet available to U.S. consumers. Launched in 2013, Kraken says it has 7 million clients. It said its May trading volume grew more than sixfold from January.

The last five months have been pretty unreal at Kraken, said Welch. We’ve seen a surge in new clients and in all-time highs.

The app does not yet allow credit and debit card payments, but the company says it plans to enhance its offerings in the coming weeks and months.

The company said it doesn’t offer service to residents of New York and Washington state due to the cost of maintaining regulatory compliance.

The move into the U.S. market comes at a time of regulatory uncertainty and in the midst of a particularly volatile cycle. While bitcoin has quadrupled in value in the past year, the price has dropped more than 40 percent from its high in April.