Cover Page by Stephen Woods

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3. Speeding Up the First Load

The first contact users have with a site is when they begin to form an opinion about whether or not it’s “slow.” If the first load feels sluggish, particularly on a mobile connection, users may go away before it finishes and never come back. Making that first load fast is the most fundamental thing a developer needs to do when making a site responsive.

The speed of the first load is measured in “time to first byte,” that is, the time from when the user requests the page to when the first byte starts to come down from the server. Although this is important to know, measure, and optimize, in the vast majority of cases this is not the cause of first load slowness. The problem commonly lies on the front end. PageSpeed, ...

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