UPDATE: PHP 8 and Xdebug 3 2021.07.18 Ok this took a bit since the Xdebug site talks about arch -x86_64 sudo pecl install xdebug which did not work. I just did the normal sudo pecl install xdebug Then I edit the addition it made: /opt/homebrew/etc/php/8.0/php.ini zend_extension="xdebug.so" xdebug.mode = debug xdebug.start_with_request = yes I moved it all to the bottom of the file too. The docs talk about OPCache but not sure this really helped.