Server response time is a value consisting of the time spent on the path from the customer to the server and back, as well as the time of script execution.
We can influence the first component indirectly by moving the account to another server. We recommend using a server located closer to your target audience.
The second component is the speed of script processing. It is determined by the optimization of the PHP code and the speed of its processing by the interpreter. In the versions PHP 7.0 and higher, a faster interpreter is used, so it is advisable to specify these versions for the website.
Caching has a positive impact on response speed. Caching is a general name for moving part of data to a repository that can be accessed faster. We use the opcache module for this. The module is usually included by default and is already functioning for your website.
Profilers are used to find bottlenecks in PHP code. They cannot be launched on the hosting, as this requires a specialized environment. It is recommended to debug the code on the local server. You can read an overview of profilers online. Code debugging requires good programming skills.