BuiltWith is a tech profiling tool that catalogs the technologies used by millions of websites — popular for sales prospecting and competitive research. StoreVitals detects tech stacks too, but as part of a continuous ecommerce health audit, not as a lead-gen database.
BuiltWith is a sales and market research tool — useful if you're building lead lists by 'all stores using Klaviyo' or watching platform migration trends across the industry. StoreVitals is an operational tool — useful if you want to know whether YOUR store (or the stores you manage) are healthy and which technologies they're loading. Tech stack detection overlaps in scope but the use cases barely intersect. For prospecting, BuiltWith. For monitoring, StoreVitals. Many agencies use both for different purposes.