TTFB

Time to First Byte

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Measures the duration from when a page starts loading to when the first byte of content is received from the server.Learn more

How TTFB is Calculated

You just experienced a 2-second server delay before any content appeared. This entire page demonstrates Time to First Byte.

  1. 1
    Request Initiation

    Browser initiates request for resource (HTML, API, etc.)

  2. 2
    Network Latency

    DNS lookup, connection establishment, SSL handshake

  3. 3
    Server Processing

    Database queries, API calls, content generation

  4. 4
    First Byte Response

    Server sends first byte back to client - TTFB measured here

TTFB Formula: Request Start → First Byte Received

Good≤ 0.8s
Needs Improvement0.8s - 1.8s
Poor> 1.8s
Real-world impact

High TTFB delays everything else. Users see blank pages longer, and other resources can't start loading until the HTML arrives.

Note: You experienced 2 seconds of server delay before this content appeared. Real TTFB is affected by server response time, network conditions, and backend processing.

TTFB Demo - Time to First Byte | WebVitals