Coinbase has managed to secure $25m in series B funding led by Silicon Valley-based venture capital firm Andreessen Horowitz. This brings the total amount raised by the company to $31.9m.

The firm, which describes itself as an “international digital wallet that allows you to securely buy, use, and accept bitcoin currency”, is going from strength to strength, with an estimated 600,000 people now using its wallet service, up from 200,000 in August.

The $31.9m raised so far represents the biggest fundraising success of any bitcoin company, dwarfing Circle’s $9m of Series A funding from multiple tech investors. To say that this is huge is not an overstatement.

Coinbase is getting a lot of positive press, too. Last week it was named the second most exciting tech start-up by Time magazine.

“This funding solidifies our position as the largest and fastest growing bitcoin service in the US. We plan to use the funds to expand our team, continue to educate the market, and promote the mainstream adoption of bitcoin,” Coinbase said in a statement, adding:

“We’ll also expand our referral program, where you can give and get $5 in bitcoin for free when you refer a friend who buys or sells at least $100 of bitcoin.”

Coinbase also announced that Bitcoin developer Gavin Andresen has joined the company in an advisory role. Andresen said Coinbase has already become a “critical piece of the Bitcoin infrastructure” in the United States. He added that the best part of his job as chief scientist of the Bitcoin Foundation is interacting with brilliant people at Coinbase and other start-ups who are working to bring bitcoin to a wider audience.

“We’re very excited about the investment. The team at Andreessen is very far up on the curve on their thinking on bitcoin, especially as a way to bring simple economics in to the web in a low level way,” Coinbase co-founder Fred Ehrsam told CoinDesk. “The money will allow us to continue building a world class engineering team, to continue to play offense when it comes to regulation and compliance, and to throw fuel on the fire for our referral program.”

Ehrsam said it is all about continuing to build a user experience that continues to reduce any friction in bitcoin – whether by making it easier to buy bitcoin with more pay-in options, getting more world-class merchants on board to what is the most seamless checkout experience in bitcoin, or adding to the Coinbase API, which is currently the most active developer platform in the bitcoin ecosystem.

Coinbase likes to point out that it is the only company in the bitcoin ecosystem that encompasses both consumers, merchants and developers.

“We are averaging 10,000 new customer sign-ups a day, and are now working with over 16,000 merchants including OkCupid, Khan Academy, and reddit, who use Coinbase to accept bitcoin,” said Coinbase.