An Explanation of Time to First Byte

An Explanation of Time to First Byte
Time to First Byte is not necessarily part of the Core Web Vitals but it is an incredibly valuable site speed metric that we can learn a lot from.

Definition of Time to First Byte

TTFB is measured in seconds, and is the time that it takes to request information from the server and send this information back to the browser. Another way to explain this would be to say that it is the time between when you navigate to a page and when the page starts to render.
During this time, several actions take place: 
  • A server request is sent, which can vary depending on use location and internet connection,
  • The server processes the request and generates a response, 
  • The server send information back to the browser.
Research suggests that the time that the server takes to send information back to the browser accounts for 40% of the total TTFB. 

Why the TTFB Matters

The TTFB matters because the slower your Time to First Byte, the longer it takes for your users to see content on your website. With a high TTFB, your visitors may abandon your site and shop with competitors instead, and you may start to see your search engine rankings affected if this continues to be a problem.
Time to First Byte
It’s impossible to have a 0 ms TTFB, but the consensus within SEO is to have a TTFB less than 200 ms to be considered solid. A time above 500 ms would be regarded as unsatisfactory, and around this point, your users start to experience frustration as they have to wait for the rest of the page to load. Between 200 ms and 500 ms could be ok depending on whether the content is dynamic or static, but improvements could and should still be made if this is the case.

How to Optimise for Time to First Byte

Multiple factors are involved in improving your TTFB, and Google also covers specific information relating to the most popular CMS’s. Still, there are also some specific actions that we can all make as SEOs.
Ensuring that you choose a web host with a good server is the first step. For large-scale eCommerce websites, I would undoubtedly suggest a dedicated server. For most other websites, a shared server is OK as long as the server can handle it. So try and find one that you aren’t sharing with 1000’s of other domains. Most hosting providers also offer premium DNS services, which can reduce DNS lookup times too.
I would also suggest keeping any plugins and extensions and your themes up to date and removing any that are no longer in use, as these can easily weigh down your website.
Using a CDN is another way to see quick wins. Using a CDN will significantly help if you serve visitors in international locations or even different parts of the country. Content Delivery Networks use servers in other sites to deliver content faster. Using servers closer to a visitor’s physical location reduces network latency too.
Caching should produce noticeable differences, too, as not only should you see an improvement in your overall load time, but it should help to decrease your TTFB as it helps to reduce server processing time.
The beauty of Time to First Byte is that it tends to have a domino effect on other site speed metrics, many of which are mentioned in this site speed series. Therefore, time spent improving your TTFB will help your Core Web Vitals and other page speed metrics too!

Tools for Measuring Time to First Byte

There are a variety of resources at your disposal to test Time to First Byte and monitor site speed; these are:
  1. ByteCheck – gives a clear TTFB report and shows other data points of interest, 
  2. – has more options to test by location and device and test on different browsers to see how this affects TTFB.
  3. Key CDN – tests overall performance and highlights key timings and issues affecting performance, 
  4. Chrome DevTools – found in the Network window and check the performance of your website,  
  5. Geekflare TTFB Tool – simple, quick, and lets you see how fast your Time to First Byte is from three locations around the globe.
  6. Pingdom – here, TTFB is referred to as “wait” time.
  7. GTMetrix – shows comprehensive site speed metrics, including TTFB, which is found under the Browser Timings section. 

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