UPDATE (22nd Jan 20:10 GMT): Braintree has responded to questions about US merchant adoption of its development kit and clarified that customers can only pay in bitcoin through a Coinbase account.

Merchants who use the payments software platform Braintree in the US can enable bitcoin payments through Coinbase starting today.

Braintree

said that it had integrated Coinbase into its software development kit, which it calls v.zero. This means that merchants who use the kit can now enable bitcoin payments quickly, Braintree said.

"Bitcoin is growing in popularity for consumer and merchants alike ... the number of companies both small and large working to enable bitcoin acceptance is on the rise," Braintree said in a blog post announcing the move.

Braintree, a subsidiary of PayPal, wouldn't reveal the number of US merchants who use its development kit, saying only that it has seen "widespread adoption" of the software tool since it was released in July. The integration will require customers to have Coinbase accounts in order to pay merchants in bitcoin.

Braintree had 85.7 million cards on file to use its single-click or repeat purchase feature in the third quarter of last year, according to PayPal's latest quarterly financial report.

First announced in September, the integration process required more time than expected in order to create a "seamless" experience for merchants, Coinbase said in a statement.

"We believe the extra time spent perfecting this experience will make merchants and consumers alike happy," a spokesperson said.

Braintree counts companies like Uber, Airbnb and OpenTable among its clients. Further, it allows merchants to accept payments from credit and debit cards, PayPal, Apple Pay and its mobile payments wallet Venmo.

Braintree chief executive Bill Ready is known for his optimism about bitcoin's future as a payments method, telling CoinDesk in November that his firm is working to take bitcoin mainstream.

Images via Braintree