FullStory
FullStory is a web-based digital intelligence system that helps optimize the client experience.
What detecting FullStory tells you about a site
FullStory is a session-replay and digital-experience analytics tool: its script captures DOM mutations, clicks and rage-taps to reconstruct a video-like replay of real sessions, shipping the stream to FullStory's ingestion endpoint via a window.FS / _fs_* global and config. Catching it tells you the team studies actual user behaviour at a granular, watch-the-recording level — common in UX, conversion-optimisation and product teams. Because it records so much, its presence also raises privacy questions worth noting: it captures far more than a pageview counter does.
The detail that matters for FullStory
Session-replay tools like FullStory have to grapple with masking sensitive fields; spotting it on a page handling payments or personal data is a signal worth flagging, since misconfigured masking is a recurring compliance pitfall.
FullStory in a real-world stack
When you find FullStory, it rarely travels alone. Sits alongside a product-analytics tool (Amplitude, Mixpanel) and a heatmap/feedback layer, all measuring the same sessions from different angles.
About
FullStory is a web-based digital intelligence system that helps optimize the client experience.
Categories: Analytics
Quick facts
Detection methodology for Analytics
Analytics SDKs are usually loaded from a vendor-controlled CDN (`googletagmanager.com`, `google-analytics.com`, `cdn.segment.com`, `cdn.amplitude.com`, `eu.i.posthog.com`) and expose a global with a recognisable surface. We catch the script src URL plus the global plus — when a sourcemap is available — the exact `node_modules/<sdk>/package.json` version. Tracker isolation prevents these vendor libraries from polluting the surrounding stack readings.
How we detect FullStory
Sourcemap Explorer carries 2 fingerprint signals for FullStory, spread across 2 channels — javascript global and script src url. The exact patterns are listed below, and you can replay each one in Chrome DevTools to confirm a match by hand.
Each signal alone is rarely conclusive — Sourcemap Explorer cross-references all of them and weights by confidence. You can reproduce any of these checks yourself in Chrome DevTools.
Window-level global the technology installs on page. Reproducible by typing the path into the DevTools console.
window.FS.clearUserCookie
Script URL pattern. Typically a CDN host or chunk path that ships with the technology.
\.fullstory\.com/
FAQ
How do I check if a website is using FullStory?
Open the page in Chrome, click the Sourcemap Explorer toolbar icon, and read the Stack tab. FullStory's specific fingerprints here are javascript global and script src url, and the popup flags FullStory whenever any combination of them is found. The same checks can be reproduced manually in DevTools — see the "How we detect" section above.
What FullStory version can Sourcemap Explorer detect?
FullStory ships as a hosted analytics rather than a bundled npm package, so version-specific detection isn't always possible. Where the platform leaks a version in response headers (`X-Powered-By`, `Server`, generator meta tags) we surface it; otherwise we report presence only.
Is FullStory a SaaS or self-hosted?
FullStory is offered as a hosted SaaS product. Detection runs against the JavaScript SDK or asset-URL fingerprints the platform ships into pages.
How much does FullStory cost?
FullStory's pricing model is documented as: freemium, mid, recurring. Detection is independent of the pricing tier — Sourcemap Explorer flags the technology by its fingerprints, regardless of which paid plan a site is on. See the official site for the current pricing page.
Where can I read more about FullStory?
Official site: https://www.fullstory.com. For Sourcemap Explorer's detection guide, see the deep-dive link below or the related guides in the cross-link section.
Keep reading on Sourcemap Explorer
Practical guides
Alternative tools
Detected by Sourcemap Explorer
Open the popup on any page running FullStoryand you'll see the exact version pulled from the bundled package.json when sourcemaps are exposed.