BuiltWith

A solo-built technology profiler that reveals the tools, frameworks, and services powering any website on the internet. Founded in 2007 by Gary Brewer as a side project, it grew into a powerful SaaS platform used by sales teams, marketers, and competitive analysts to identify technology adoption trends across millions of sites. The product was built and scaled by a single developer with minimal overhead, reaching approximately $1.2M in monthly revenue through tiered subscription plans — making it one of the most profitable solo-founder SaaS businesses ever created.