The “Reduce initial server response time” warning is triggered by PageSpeed Insights when your time-to-first-byte (TTFB), also referred to as wait time, is higher than 600 ms (source). High TTFB happens when caching isn’t set up properly, or your website isn’t hitting cache. It also has a big impact on First Contentful Paint (FCP) and Largest Contentful Paint (LCP).
We always recommend running your speed test at least three times. If your site’s cache just expired, you might see the above warning the first time you run the test. If you do have caching properly set up, this warning will go away with a repeat test. If it doesn’t, you might need to install a caching plugin or check your caching configuration.
Fix the “Reduce initial server response time” warning
Here are a couple of things you can do to fix the “Reduce initial server response time” warning, along with some recommendations.
- Install a caching solution
- Clear cache less often
- Increase cache length
- Decrease the distance of your server
- Invest in fast hosting
Install a caching solution or plugin
The very first thing you should do is check to ensure you have a proper caching solution or plugin in place on your WordPress site. If you’re using a managed WordPress hosting provider like Kinsta, this should simply work out of the box, as they have server-level caching. There is no configuration or caching plugin needed. That’s the beauty of a managed WordPress host.
If you’re using another type of hosting provider, you will most likely need to install a caching plugin. We recommend the following caching plugins (these all work great alongside Perfmatters):
- WP Fastest Cache (free)
- Super Page Cache for Cloudflare (free)
- WP Rocket (premium)
Clear cache less often
This might seem obvious, but once you’re done optimizing, it’s recommended that you don’t clear your entire site cache too often. The more uncached crawls or hits to your site can actually hurt your Core Web Vitals scores over time. You want your site to hit cache as much a possible.
If you’re curious, we have a regular plugin update schedule every two weeks, where we back up sites, update plugins (test them), etc. We then do a full site cache clear. So on our sites, we’re never clearing the cache more than twice per month (unless something goes wrong). The longer things are cached, the faster they will be for users and Google when they crawl your site.
Increase cache length (TTL)
A great way to reduce the “Reduce initial server response time” warning from showing frequently is to increase the cache expiration time (TTL) on your site. Longer cache times lead to improved site performance, and better cache HIT ratios. It can also fix the warning from Google to “serve static assets with an efficient cache policy.”
If you’re hosting with Kinsta, the following cache length times are available right from the MyKinsta dashboard:
- 1 hour
- 2 hours
- 4 hours
- 8 hours
- 24 hours
- 7 days
If you’re using a different hosting provider or caching plugin, check their documentation or ask their support to see how to increase your WordPress site’s expiration time.
If you’re using full-page caching with Cloudflare, you can also change this from their dashboard. Under the “Caching” tab, click on the “Configuration” tab. Set your “Browser Cache TTL” to something higher. We recommend at least 7 days or a month.
Decrease the distance of your server
As mentioned above, high TTFB can trigger the “Reduce initial server response time” warning from PageSpeed Insights. If your server is hosted in the United States, and someone is visiting it from Germany, this will result in higher TTFB. And it could put you over the under 600 ms threshold that Google is wanting.
Why does this happen? It’s mainly due to the physical distance and the network latency involved.
However, there is a solution. And that is using Cloudflare. They have a service called Automatic Platform Optimization (APO), which caches your entire site, not just the assets but also HTML, at different edge servers all around the globe, eliminating the distance problem altogether. This results in really low TTFB!
The CDN service from Cloudflare is free, and the APO service costs $5/month per domain, regardless of how much traffic you get. If you’re curious, we’re using Cloudflare’s APO service on this website. All you do is sign up for APO and install the free Cloudflare WordPress plugin. It works great with our Perfmatters plugin.
Make sure to also check out our recommended settings for Cloudflare for the best performance.
Invest in fast hosting
Another reason you might see the “Reduce initial server response time” warning is that you’re using a slow WordPress hosting provider. You get what you pay for when it comes to hosting. Many cheap hosting providers try to get as many customers onto one server as possible. This results in you sharing all of the server’s resources with everyone else, in turn slowing down your site. We always recommend investing in fast WordPress hosting where many of these headaches disappear.