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Response Time Tester

Measure DNS, connection, TLS, TTFB, and download time for any URL.

The request breakdown helps separate DNS, connection, TLS, server, and transfer delays.

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Reading the timing breakdown

The test separates the main phases of one HTTP request:

DNS Lookup resolves the domain name to an IP address. Slow DNS can add hundreds of milliseconds before your server even sees the request. TCP Connect establishes the network connection. TLS Handshake negotiates encryption for HTTPS connections. Time to First Byte (TTFB) measures how long the server takes to start sending a response after receiving the request, which is the strongest indicator of backend performance. Download is the time to transfer the full response body.

What is TTFB?

Time to First Byte (TTFB) is the duration from when the client sends the request to when it receives the first byte of the response. A TTFB under 200ms is considered fast, 200 to 500ms is acceptable, and anything above 600ms may indicate server-side performance issues. TTFB is influenced by server processing time, database queries, and geographic distance between client and server.

Monitor response time

A one-time test is a snapshot. Website monitoring records response time over repeated checks and can alert on failures or sustained degradation.