For testing purposes, I would like to append a query string (let's say testing=true) to any url requested from my website. #E.g. I want to change example.com example.com/product example.com/search?q=string to example.com?testing=true example.com/product?testing=true example.com/search?q=string&testing=true Answer: <IfModule mod_rewrite.c> RewriteEngine On RewriteCond %{QUERY_STRING} !(^|&)testing=true(&|$) [NC] RewriteRule ^ %{REQUEST_URI}?testing=true [L,QSA,R] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteCond $1 !^(index\.php|public|images|robots\.txt|css) RewriteRule ^(.*)$ index.php/$1 [L] </IfModule>