A free, local-first alternative to NerdyData

Overview

NerdyData is a web-wide source-code search engine rather than a technology detector. You paste an HTML snippet, a JavaScript string or a regex, and NerdyData tells you which sites across its crawl index contain that pattern. It's closer in spirit to a full-text search for the HTML/JS of the web than to Wappalyzer. Developers occasionally use it for competitive research ('find every site using this exact embed code'), and it has a lead-generation dressing on top that mirrors BuiltWith's sales positioning.

That 'search across the web' framing is genuinely distinctive. Most of the alternatives on this page detect things from a fingerprint database; NerdyData lets you write the fingerprint as an ad-hoc query. If you suspect a specific snippet (a tracking pixel, a script tag, a CSS class name, a meta tag) identifies a specific tool — even one nobody has fingerprinted — you can confirm or refute that suspicion in seconds and immediately get a list of sites that share the pattern. That capability is genuinely unique in the category, and Sourcemap Explorer does not try to compete with it. We answer 'what is on this page'; NerdyData answers 'what other pages also have this'. The two products coexist by occupying complementary positions on a 'depth on one site' vs 'breadth across many sites' axis.

History

NerdyData launched around 2012 as a search engine for the web's source code. Its initial positioning was developer-research-friendly — 'grep the web for code' was the elevator pitch — and its earliest userbase was security researchers, web archaeologists and competitive-intel curious developers. Over time it accumulated sales-team framings (lead lists by installed technology patterns, integrations into common sales tooling) that are now the main revenue driver.

The company has not had the explosive growth of the SimilarWeb-class technographic players, partly because the underlying product is harder to monetize at scale (search-engine intent does not always map to sales intent) and partly because the addressable audience is naturally smaller than the broad 'tell us what these sites use' audience that Wappalyzer and BuiltWith serve. The product persists, the index keeps getting refreshed, and the developer-curiosity tier remains a usable surface, but the strategic centre of gravity has clearly drifted towards sales workflows over the years. By 2026 NerdyData reads more like a sales tool with a developer-research surface than a developer tool with a sales upsell.

Who uses it and for what

Developers use it as a search engine — 'find every site including gtag.js with this specific GA property ID', 'find every site that loads this CDN URL', 'find every site embedding this Vimeo player ID'. The use cases tend to be investigative: tracking down where a leaked API key is used, mapping the footprint of a compromised script, finding the cohort of sites that share a specific build artifact, doing supply-chain or attribution work that needs cross-domain evidence.

Sales teams use it to build lead lists keyed off source-code patterns (e.g. 'every site embedding the Calendly widget', 'every site with the Crisp chat snippet', 'every site loading a competitor's tracking pixel'). Security researchers occasionally use it to enumerate the victim footprint of a supply-chain incident — 'how many sites currently load the compromised analytics script' — which is exactly the question NerdyData's index shape is best at answering. None of those use cases overlap with what a developer wants from a per-page detector like Sourcemap Explorer; they are different jobs that happen to share the word 'detect' in marketing copy.

Pricing in detail

What NerdyData does well

Where NerdyData falls short

These are the gaps a developer-first, sourcemap-aware workflow cares about.

Where Sourcemap Explorer wins

Not across the board — we don't run bulk API queries and we don't publish market-share dashboards. These are the things we do that NerdyDatadoesn't.

NerdyData vs Sourcemap Explorer

Side-by-side on the dimensions a developer studying a single page actually cares about.

A concrete workflow example

Supply-chain security incident: a popular analytics script is discovered to have been compromised between commits 4f2a and 5b91. The security-engineering team needs to assess the blast radius and prioritize the response. NerdyData is the right tool for 'how many sites across the web currently include this URL?' — they paste the script src into the NerdyData query box, get a count and a sample of the affected domains in seconds, and use that to estimate the scale of the incident. That's NerdyData's bread and butter.

In parallel the same team needs to answer 'does our own product surface, and the internal admin tools we use, load this library anywhere?' — and that question NerdyData cannot answer, because their crawler does not have access to your authenticated internal dashboards or your customer staging environments. They open Sourcemap Explorer, browse through the relevant internal tools and product surfaces themselves, and get an authoritative local read of which of their own pages depend on the compromised script. NerdyData scoped the global blast radius; Sourcemap Explorer audited the local exposure. Both reads land in the post-incident report.

Which one should you use?

FAQ

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