Wordpress slow on azure

Try to enable Always On in the Settings. 20 seconds is a very serious number, but Always On should eliminate the issue with the cold start.

UPD: Next step - enable Application Insights (performance monitoring in the settings) to see what is going on with your performance. It is really difficult to say what can be a problem - you can check if your DB and your website are in the same region (however, i did not experience such numbers because of that).

It is due to PHP's output buffering, which is not configured on Azure WebApp.To resolve this you can add the following code in the web.config file and restart your WebApp.

<configuration>      <system.webServer>         <handlers>            <add name="PHP-FastCGI"                path="*.php"                verb="GET,HEAD,POST"                modules="FastCgiModule"                scriptProcessor="D:\Program Files (x86)\PHP\v5.4\php-cgi.exe"                resourceType="Either"                requireAccess="Script"                 responseBufferLimit="0" />         </handlers>      </system.webServer></configuration>

Please check this reference for improving WordPress Performance on Azure Web Apps: https://blogs.msdn.microsoft.com/azureossds/2016/05/15/improving-wordpress-performance-on-azure-web-apps/