Yottaa Inc., a Boston-based company providing Web optimization services, said Tuesday that it has closed $9 million in Series B funding.

All existing investors, including General Catalyst Partners, Stata Venture Partners, and Cambridge West Ventures, returned for this round and were joined by additional undisclosed investors, Yottaa said.

Yottaa describes its offering as an “easy-to-use cloud service that brings speed, scale, and security” to a business customer’s website. With Yottaa’s services, a customer’s website can achieve faster page loads and enjoy higher search engine rankings, while being protected from failures that result from heavy traffic, the company claims.

According to Yottaa’s website, customers include Sears, Rue La La, and Sony Music.