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Full Version: how to improve first byte
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Hello ,
How do you know where in the report where we can improve the first byte? Is the first byte of each request or the URL request?


We got an F for the first byte.


It's the time from the start of the test until the first byte of the base page. The 2 redirects in this case are absolutely killing you (though the 780ms for the base page isn't helping either).

The baseline is calculated based on the socket connect time for the first request which is used as a proxy for the Round Trip Time (53 ms in this case). Then it allows for the DNS lookup, socket connect and http request times (3*RTT). If the server responds within 100ms after that you get an A and it deducts a grade for every 100ms after that.

I might lighten up the timings a bit but the first byte time is absolutely critical since the browser can't download any other resources or display anything to the user until it gets some data to work on.

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