ua-tracer
by Paul Kinlan
trace zt5xsuvE
what does a user agent actually fetch, follow & run?
Trace zt5xsuvE
First seen: 2026-08-06 10:48:34.402 UTC
User-Agent: Mozilla/5.0 (compatible; jscrawler/0.1; +https://github.com/)
Bot verification: Not a known bot (no IP-range check applies).
What this user agent did
Directly-referenced assets:
✗ fetched CSS
✓ fetched JS
✗ fetched image
✗ fetched font (HTML)
Document-level link hints:
✗ fetched favicon
✗ fetched apple-touch-icon
✗ fetched web manifest
✗ fetched preload
✗ fetched prefetch
Second-level follows (proves it parsed the linking file):
✗ followed CSS background-image
✗ followed CSS @font-face
✗ followed manifest icon
✗ followed CSS @import
Frames (does it descend into iframes?):
✗ fetched iframe document
✗ descended into iframe (loaded inner image)
Reporting (a report-only CSP is violated by inline styles; reports can arrive via HTTP headers with no JS, or via in-page beacons):
✗ sent a CSP/Reporting report (any path)
✗ delivered via report-uri/Report-To header (no JS)
✗ delivered via in-page beacon (securitypolicyviolation / ReportingObserver)
Social embed (Open Graph / Twitter card images):
✗ fetched og:image
✗ fetched twitter:image
JavaScript execution:
✗ EXECUTED classic JS
✗ EXECUTED ES module
✗ posted client timing
Server-side request waterfall
Every request the server received for this trace, in receive order. +ms is the delta from the
homepage request.
| Received | Δ | Kind | Method | User-Agent |
|---|---|---|---|---|
| 2026-08-06 10:48:34.402 UTC | +0 ms | homepage | GET | Mozilla/5.0 (compatible; jscrawler/0.1; +https://github.com/) |
request headers (9){
"accept": "*/*",
"accept-encoding": "gzip,deflate,br",
"host": "uatracer.com",
"traceparent": "00-3be9cc47be46b42eea87722068c29d25-1c85c87721c2432d-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (compatible; jscrawler/0.1; +https://github.com/)",
"via": "HTTP/1.1 ams.vultr.prod.deno-cluster.net",
"x-deno-userspace-traceparent": "00-3be9cc47be46b42eea87722068c29d25-98aeca4672a8d072-01",
"x-deno-userspace-tracestate": ""
}
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| 2026-08-06 10:48:42.181 UTC | +7779 ms | ES module | GET | Mozilla/5.0 (compatible; jscrawler/0.1; +https://github.com/) |
request headers (9){
"accept": "*/*",
"accept-encoding": "gzip,deflate,br",
"host": "uatracer.com",
"traceparent": "00-e30ff177d343e82386eff713b5b6a0c5-35efece73ffe8bb6-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (compatible; jscrawler/0.1; +https://github.com/)",
"via": "HTTP/1.1 ams.vultr.prod.deno-cluster.net",
"x-deno-userspace-traceparent": "00-e30ff177d343e82386eff713b5b6a0c5-96ae10d95c87bf02-01",
"x-deno-userspace-tracestate": ""
}
|
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| 2026-08-06 10:48:42.201 UTC | +7799 ms | JS | GET | Mozilla/5.0 (compatible; jscrawler/0.1; +https://github.com/) |
request headers (9){
"accept": "*/*",
"accept-encoding": "gzip,deflate,br",
"host": "uatracer.com",
"traceparent": "00-f6c7473e77084dbcc632f51e6bf1e252-196d767f9f6a5e98-01",
"tracestate": "",
"user-agent": "Mozilla/5.0 (compatible; jscrawler/0.1; +https://github.com/)",
"via": "HTTP/1.1 ams.vultr.prod.deno-cluster.net",
"x-deno-userspace-traceparent": "00-f6c7473e77084dbcc632f51e6bf1e252-6589e8757f81f9b9-01",
"x-deno-userspace-tracestate": ""
}
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