Online video calling service TokBox has pulled down $10 million in series B financing as the San Francisco startup seeks to fill out its executive ranks and initiate a global expansion, the company said Thursday.

Bain Capital Ventures, which led the round, was joined by Sequoia Capital, which spearheaded the $4 million A round in 2007. The company also is backed by angels and Youniversity Ventures, whose founders include Jawed Karim, a co-founder of YouTube.

TokBox is taking on larger video chat and calling competitors like eBay’s Skype, AOL’s AIM, Apple’s iChat and Microsoft’s MSN, but seeks to differentiate itself by providing a browser-based service that requires no download and allows users to send a video voicemail to anyone with an e-mail address, regardless of whether they are TokBox users.

Scott Friend, a venture partner at Bain Capital Ventures and a new board member at TokBox, said technology is migrating from computer-based software to programs residing on the Web.

“We think a similar phenomenon will take place in the video-chat world,” he said and while Yahoo Messenger does offer web-based video chat, users can’t connect with people outside the network.

Mr. Friend said TokBox users recently passed the million-minutes-per-day milestone. The 10-month-old company remains focused on adding users for now, he added, but eventually could seek revenue by placing advertisements in and around the video screen and selling professional features to recruiters and business users.

In addition to providing service through its web site and via a Firefox add-on for Facebook users, TokBox powers the video-chat service of instant-messaging aggregator Meebo, which brings together the services of AIM, MSN, Yahoo, ICQ and others.

Mr. Friend noted that TokBox, which already had participation from a premier Silicon Valley venture firm in Sequoia, was attracted to Boston-based Bain Capital Ventures because of its connections to Wall Street and the network of companies in the portfolio of its private-equity parent, Bain Capital.

TokBox, whose users are “predominantly” Americans, plans to push into foreign markets, Mr. Friend said, an opportunity “as big or bigger as what we have domestically.”

The company also plans to offer mobile video mail, though not all handsets have cameras on the same side as the video screen, Mr. Friend noted.