💡 SaaS Idea: ReverseBuilt

Reverse lookup of sites using a specific SaaS/tool or library. Enter a vendor (e.g., Intercom) and get a list of sites detected by web crawling + tech fingerprinting.

Platform: web

Why it's a good idea?

1. Problem & Solution Recap

Marketers, sales teams and investors often want lead-lists of sites that use a given technology ("Which sites run Intercom? Who’s using Stripe, React, Tailwind … ?"). ReverseBuilt promises to crawl the web, fingerprint tech stacks and return those lists.

2. Evidence of Demand in the Wild

  • Reddit thread supplied by the founder already shows someone looking for exactly this (“Is there a tool that can tell me all the websites …?” – r/MarketingResearch).
  • Dozens of similar threads in r/sales, r/leadgen, IndieHackers, HN ask “how to find companies using ”.
  • Hunter.io’s TechLookup publicly shows downloads >1 M (counter on landing page) – clear usage.

3. Existing Players / Competitors

Product Cheapest paid plan Positioning
BuiltWith $295/mo Market leader, exhaustive DB, heavy UI/UX debt
Wappalyzer $149/mo Chrome extension + API, good breadth but low export limits
SimilarTech $199/mo Focus on enterprise, UI dated
Hunter TechLookup €99/mo (with other Hunter tools) Mainly email outreach market
NerdyData, DataFragment, Foxtail.so, TheirStack, Ful.io, AppsRunT...
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