Rakuten Inc. has agreed to buy U.S. rebates website Ebates Inc. in Japan's largest-ever e-commerce deal as the operator of the country's biggest online mall seeks overseas growth through acquisitions.

Rakuten will pay $1 billion in cash for all of Ebates, it said in a filing Tuesday to the Tokyo Stock Exchange.

San Francisco-based Ebates offers cash rebates to customers who buy products ranging from laptops to lipsticks from the website's retail partners.