Response timing
Response Timing Curve Analyzer
Enter a target URL and use browser Fetch plus the Performance Timing API to chart one visit across redirect, DNS, TCP, TLS, TTFB, and download phases.
Browser timing limitations
For cross-origin sites that do not send Timing-Allow-Origin, browsers hide detailed DNS, TCP, TLS, and TTFB fields. This page keeps the total duration it can read and marks restricted segments. For production-grade numbers, recheck with a server-side probe or curl.
Waiting for a URL
Enter a URL, choose GET or HEAD, then run a browser-side response timing check.
Result summary
Timing curve
StartComplete
Segment timing
| Segment | Duration | Share | Note |
|---|---|---|---|
| Redirect | - | - | HTTP redirect chain duration, visible only when redirects are followed and the browser exposes the field. |
| DNS | - | - | Domain lookup time; cached lookups may be close to 0 ms. |
| TCP | - | - | TCP connection setup time; HTTPS handshakes are split into the TLS segment. |
| TLS | - | - | HTTPS handshake time; HTTP requests or hidden browser fields show 0 or restricted. |
| TTFB | - | - | Time from request start until the first response byte, useful for origin and network wait analysis. |
| Download | - | - | Transfer time from first byte to response completion, affected by body size, bandwidth, and browser policy. |
Diagnostics
Built for these checks
TTFB triage
Quickly see whether first-byte wait is much higher than DNS, connection, and download phases.
TLS / connection review
For sites that expose Timing data, compare TCP and TLS setup against the full request.
Frontend support replay
Repeat GET/HEAD, redirect, and total-duration checks from the same browser for support or ops handoff.
FAQ
Why do some segments show restricted?
Browsers protect cross-origin timing detail. Unless the target sets Timing-Allow-Origin, DNS, TCP, TLS, TTFB, and similar fields may be hidden.
Does this replace server-side curl timing?
No. It reflects the current browser view. Production debugging should still combine curl, server probes, CDN logs, and APM data.
What is the difference between GET and HEAD?
HEAD usually skips the response body and is useful for connection and first-byte checks. GET is closer to a real page or API visit but includes body transfer cost.