Page Speed Checker

Measures the real network timings of the request — DNS, TCP, TLS, time-to-first-byte, and total download — using Node's low-level socket events for sub-millisecond accuracy. Then probes the top scripts, stylesheets and images for size. Server-side measurement, so it doesn't depend on your browser.

Server Response Latency & Low-Level Network Timings

Page loading speed begins at the transport layer before any browser rendering takes place. Measuring low-level network socket events—DNS resolution, TCP connection establishment, TLS cryptographic handshake, and Time-To-First-Byte (TTFB)—pinpoints backend infrastructure bottlenecks independent of client device capabilities.

The Network Request Lifecycle

1. DNS Lookup (Target: < 50 ms): Domain Name System query converting hostnames to IP addresses. Mitigate high latency with globally distributed Anycast DNS resolvers.

2. TCP Handshake (Target: < 50 ms): Three-way SYN/ACK handshake establishing bidirectional socket communication.

3. TLS Handshake (Target: < 100 ms): Cryptographic parameter negotiation and certificate exchange. Modern TLS 1.3 standardizes 1-RTT handshakes (and 0-RTT resumption) compared to 2-RTT in TLS 1.2.

4. Time-To-First-Byte (Target: < 200 ms): Server-side processing, routing execution, and database querying before transmitting the first HTTP response byte.

Server Latency vs. Browser Core Web Vitals

While this tool evaluates origin network timings, search engines assess the complete client rendering pipeline via Core Web Vitals:

  • Largest Contentful Paint (LCP): Measures when the main viewport content finishes rendering (target ≤ 2.5s). Delayed by high TTFB and uncompressed hero images.
  • Interaction to Next Paint (INP): Measures UI responsiveness to user input (target ≤ 200ms). Delayed by monolithic JavaScript main-thread execution.
  • Cumulative Layout Shift (CLS): Measures visual stability during loading (target ≤ 0.1). Caused by unsized images and dynamically injected ads.

Remediating High TTFB and Backend Latency

  • Edge Caching: Cache static HTML and dynamic responses at edge CDN points of presence (Cloudflare, Fastly, CloudFront).
  • Database Indexing: Optimize slow queries and unindexed foreign keys that block response generation.
  • Compression: Verify Gzip or Brotli encoding with our Gzip Checker.
  • Asset Payload Auditing: Inspect transfer sizes with our Page Size Checker.

Frequently Asked Questions

Why are server-side socket timings more accurate than browser extensions?

Browser extensions and client hardware throttle CPU cycles and inject third-party scripts that distort timing data. Node socket measurements isolate pure server and network performance.

What causes TLS handshake delays over 500 ms?

Long TLS handshakes typically result from missing intermediate certificates, lack of OCSP stapling (forcing the client to query certificate revocation servers), or outdated TLS 1.0/1.1 cipher negotiation.

How does mobile responsiveness impact perceived speed?

Mobile devices operate under constrained CPU power and cellular network latency. Verify viewport scaling and layout responsiveness using our Mobile Friendly Test.