The Euclid Zero package allows retailers to measure shopper activity in-store by tracking the wi-fi signals given off by mobile phones.

Previously this required a sensor to be fitted within the store, however Euclid’s technology is now available as a software option for customers of Aerohive Networks, Aruba Networks, Fortinet and Xirrus, accessible via wi-fi management consoles.

Euclid is able to count shoppers whether or not they connect to a store’s wi-fi network. In its privacy policy it explains that it “collects only basic device information that is broadcast by wi-fi enabled phones. This does not include any sensitive data such as who you are, whom you call, or the websites you visit”.

Data is anonymous and aggregated, however shoppers can opt-out by logging their phone’s MAC address at Euclid’s website.

The company launched in 2011 with $5.8m in venture capital funding. Scott Crosby, one of Euclid’s founders, previously co-founded Urchin Software, whose product became Google Analytics after it was acquired by Google in 2005.

Euclid has 30 customers, including clothing stores, quick-service restaurants, shopping malls and department stores.