Building a Privacy-First Price Alert System: Zero Cookies, Full Trust

"We need to see what products users are tracking." That's what our analytics team asked for during a product meeting. Seems reasonable, right? Understanding user behavior helps build better products. But here's what they were really asking: permission to collect data about users' shopping interests, price sensitivities, browsing patterns, and purchasing intentions. In other words, everything a traditional price tracker does without thinking twice. We said no. That decision led us down a path that seemed crazy at first: building a price alert system that genuinely doesn't know what users are tracking . At Avluz.com , where we monitor prices across 10,000+ products from Amazon, eBay, and Walmart, we've proven you can build powerful features without sacrificing user privacy. Here's how we achieved zero cookies, 100% local-first processing, and 12,000 users in our first quarter —all while staying completely GDPR compliant. The Privacy Problem Nobody Talks About Most price trackers are surv