Stanford roommates launch AI shopping app that cuts carbon footprint by 80%

Phia, an AI-powered shopping platform founded by Stanford roommates Phoebe Gates and Sophia Kianni, is transforming how consumers discover and purchase items by integrating sustainability and value assessment into the shopping experience. The startup addresses what Gates calls “this giant white space” in helping shoppers understand what to buy, positioning itself as a personal shopping assistant that prioritizes both environmental impact and financial value.

What you should know: Phia operates as both a browser extension and mobile app that compares prices across new and second-hand platforms, with sustainability at its core.
• The platform integrates with more than 150 second-hand platforms and maintains a database of over 350 million items.
• Buying second-hand through Phia represents an 80% reduction in carbon footprint compared to purchasing new items, while also being cheaper.
• The service emerged from a Stanford class project but didn’t launch publicly until the founders identified the right product-market fit.

How it works: Phia’s AI technology helps users understand both immediate and long-term value of potential purchases.
• The platform shows shoppers whether a $500 handbag can be resold for $300-$400, or if a $100 fast-fashion piece will only retain $10 of its value.
• An AI shopping advisor currently in development will assess factors like deal quality, retained value, and sizing recommendations based on users’ previous orders and returns.
• The sizing insights feature is currently in beta testing with a select group of users.

Growth strategy: The founders have employed creative marketing tactics to build their audience at low cost.
• They’ve launched an ambassador program, created content documenting their startup journey, and even started a podcast.
• “The ability to acquire hundreds of thousands of downloads at a very low cost through the podcast and the various different distribution vehicles has been really important,” said Kianni.

What they’re saying: The founders emphasize authenticity and transparency in building their brand and connecting with users.
• “I think there was a bit of an ego death that we had to go through,” Gates said. “At first, it’s like, ‘I want to look good in all of our content.’ But if you want people to engage with it, and you want to make content at the volume that we need to, you need to be able to just pull back the curtain.”
• Gates, daughter of Microsoft founder Bill Gates, acknowledged her privileged position but noted they don’t necessarily seek his advice: “So, while my dad — I think he’s a genius — he’s not the one shopping on Phia, right? Like, he’s not hunting for the best deal across different sites.”