Performance Intelligence Panel
How Fast Is Your Browser?
Live page load waterfall — TTFB, DNS, TCP, TLS, DOM, memory, and resource stats — measured the moment this page loads.
Understanding Every Signal
What each timing and resource measurement above actually captures.
Load Timing Waterfall
Page Load Time & DOM Content Loaded
Page load time is when the browser fires the window load event — every resource (images, fonts, scripts) has finished. DOM Content Loaded fires earlier, when the HTML is parsed and the DOM is ready but external resources may still be loading. The gap between the two reveals how many heavy external resources are delaying the page from being fully ready.
Time To First Byte (TTFB) & DNS Lookup
TTFB is the time from request to the first byte of response — it's the sum of DNS lookup, TCP connection, TLS handshake, and server processing. DNS lookup is just the portion spent resolving the domain name to an IP address. A high DNS time on first load often drops dramatically on repeat visits once the result is cached.
TCP Connection & TLS Handshake
TCP connection is the time to establish the raw socket connection to the server. TLS handshake is the cryptographic negotiation that follows on HTTPS connections — this is where the certificate is verified and session keys are exchanged. HTTP/2 and HTTP/3 both reduce repeated TLS overhead through connection reuse and 0-RTT resumption.
Request Time, Response Time & DOM Processing
Request time is from sending the HTTP request to the first byte of response body — equivalent to TTFB minus the connection setup. Response time is the time to receive the complete response body after the first byte arrived. DOM processing is the time the browser spent parsing HTML and constructing the DOM tree from the complete response.
Resources & Memory
Resource Fetch Time, Count, Page Weight & Cache Hit Rate
Resource fetch time covers all sub-resource loading after the main document. Count, weight, and the breakdown by type (scripts, stylesheets, images, fonts) describe the page's resource profile. Cache hit rate measures what percentage came from local cache versus the network — a high rate on repeat visits means the site is well-configured for caching.
JS Heap Used, Total & Limit
JS heap used is how much memory JavaScript has currently allocated. Total is the total heap size the engine has reserved. Limit is the maximum the browser will allow before throwing an out-of-memory error. Heap used growing over time without declining suggests a memory leak. These values are only available in Chromium-based browsers — Firefox doesn't expose them.
Next Hop Protocol, Runtime Score & Percentile Rating
Next hop protocol shows whether your connection to this server used HTTP/1.1, HTTP/2, or HTTP/3 — newer protocols generally reduce latency for multi-resource pages through multiplexing. Runtime score and percentile rating are composite judgements of the overall performance profile, contextualised against typical values for this type of measurement.
What These Numbers Tell You That Synthetic Speed Tests Don't
This is your real load, not a controlled test
Synthetic speed tests measure download bandwidth under ideal conditions. The Performance panel measures how your actual browser loaded this actual page — including your cache state, DNS resolver speed, geographic distance to the server, and the overhead of running all the other intelligence engines simultaneously. It's a real-world measurement, not a synthetic benchmark.