Wi-fi based attribution startup Zenreach has emerged from stealth, announcing that the company has raised $50m ($38) in investment and attracted the attention of Peter Thiel, co-founder of PayPal, who has joined the firms board.

Zenreach uses wi-fi to help bricks-and-mortar retailers track how many times customers return to locations and link up digital and physical marketing efforts. When customers log in to a stores free wi-fi using their email address, merchants can track any return visits they make.

The firm was established in 2013 but has remained in stealth until now, quietly raising $50m over the course of three funding rounds and growing its staff to around 150 members.

The companys Series B round totaled $30m and was led by Thiel in his role as a partner at venture capital firm Founders Fund. Thiel was also an early investor and board member for Facebook.

“Its great to partner with Jack (Abraham, founder of Zenreach) in a space hes been thinking about for so long,” said Thiel. “Online merchants rely on sophisticated analytics and marketing campaigns to attract customers. Zenreach levels the playing field for brick-and-mortar businesses by arming them with equally powerful tools.”

Zenreachs offering uses a software-as-a-service model, enabling retailers to build a customer list, differentiate between varying types of consumers, and automate marketing efforts based on physical visits to stores.

According to the firm, over a third of the population of San Francisco, where the company is based, has signed up to the service to access free wi-fi while shopping, and with its latest funding, Zenreach plans to expand its staff and open new offices internationally.

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