Metrics Reference
CDNPulse collects browser Resource Timing data from real user sessions. Each monitored file is loaded by the CDNPulse script, measured by the browser, and sent to the analytics dashboard.
Quick answer
CDNPulse metrics describe how long monitored static assets take to load for real users. The main timing fields come from the browser Resource Timing API: DNS lookup, connection, TLS, request, response, fetch, and total duration. CDNPulse also records transfer size and geographic context when available, so teams can compare CDN behavior by country, city, provider, file type, and cache setup. Lower timing values usually mean faster delivery, but fair comparisons require similar file sizes, cache rules, and response headers. For cross-origin files, the asset response should include Timing-Allow-Origin; without it, browsers hide parts of the timing breakdown. Use total duration for a headline comparison, then inspect DNS, connection, TLS, request, and response fields to understand whether delay comes from routing, connection setup, origin/cache behavior, or download speed. Review p75, p90, and p95 values as traffic grows, because averages can hide regional spikes and slow edge cases.
Timing metrics
All timing values are reported in milliseconds.
| Metric | Meaning |
|---|---|
| Total duration | Time from request start until the response finishes. This is the headline loading time for a monitored asset. |
| DNS lookup | Time spent resolving the asset hostname to an IP address. |
| Connection | Time spent establishing the TCP connection. |
| TLS | Time spent on the SSL/TLS handshake for HTTPS requests. |
| Request | Time from sending the request until the first response byte is available. This is commonly close to TTFB. |
| Response | Time spent receiving the response after the first byte arrives. |
| Fetch | Time from the browser fetch start until response completion. |
Lower values usually mean faster delivery, but compare assets with similar size and cache behavior. A large image and a tiny CSS file should not be treated as equivalent tests.
Transfer metric
Transfer size is the number of bytes the browser reports for the monitored asset transfer.
Use it to check that:
- Compared files are similar enough to produce a fair CDN comparison.
- A CDN or origin is not returning an unexpectedly different payload.
- Analytics volume is reasonable for the amount of user traffic.
Geographic metrics
CDNPulse groups requests by country and city when location data is available. These metrics help identify where CDN performance is strong or weak for actual visitors.
City-level charts become more useful as request volume grows. Small samples can be noisy, especially when users are spread across many regions.
Data quality
For accurate cross-origin timing, monitored assets should return:
Timing-Allow-Origin: *or a header scoped to your site:
Timing-Allow-Origin: https://example.comWithout this header, browsers hide detailed cross-origin timing fields. CDNPulse can still receive some data, but the timing breakdown may be incomplete.