The European Union on Tuesday approved Microsoft's mega buyout of the professional networking site LinkedIn, provided the US tech giant meets commitments to allow fair competition.

"Today's decision ensures that Europeans will continue to enjoy a freedom of choice between professional social networks," EU competition chief Margrethe Vestager said.

The deal, Microsoft's largest ever acquisition, will allow the company to add a suite of sales, marketing and recruiting services to its core business products as it gears up for next-generation computing.

The bulk of LinkedIn's $3 billion annual revenue comes from job hunters and recruiters who pay a monthly fee to post resumes and connect with people.