Upwork, formerly Elance-oDesk, is a global online work platform where businesses and independent professionals connect and collaborate remotely. In 2015, Elance-oDesk was rebranded as Upwork. It is based out of Mountain View and San Francisco, California.Upwork has nine million registered freelancers and four million registered clients. Three million jobs are posted annually, worth a total of $1 billion USD, making it the world's largest freelancer marketplace.