Options -Multiviews
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-s
RewriteRule ^(.*)$ api.php?x=$1 [QSA,NC,L]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^(.*)$ api.php [QSA,NC,L]
RewriteCond %{REQUEST_FILENAME} -s
RewriteRule ^(.*)$ api.php [QSA,NC,L]
</IfModule>