I have xdebug working locally for 'normal' sites (I am using google chrome with xdebug helper and phpstorm to talk to a site hosted on a vagrant box).
However if I try and connect to a locally hosted api site (also on a vagrant box) using a REST client (google chrome's advanced rest client plugin) it will not work.
What settings do I need for xdebug on the vagrant box, and what additional information do I need to include when making api calls?
My settings (on the vagrant machine) which work for phpstorm and vagrant box are as follows:
;;;;;;;;;;;;;;;;;;;;;;;;;;
; Added to enable Xdebug ;
;;;;;;;;;;;;;;;;;;;;;;;;;;
zend_extension="/usr/lib/php5/20100525/xdebug.so"
xdebug.default_enable = 1
xdebug.idekey = "vagrant"
xdebug.remote_enable = 1
xdebug.remote_autostart = 0
xdebug.remote_port = 9000
xdebug.remote_handler=dbgp
xdebug.remote_log="/var/log/xdebug/xdebug.log"
xdebug.remote_host=10.0.2.2
the idekey setting connects to a user defined application on phpstorm (see here: http://www.mailbeyond.com/phpstorm-vagrant-install-xdebug-php)

.cacheextension. If possible -- copy it to local project files (do not forget to associate.php.cachewith PHP files otherwise IDE will not treat it as PHP file and will not be able to step it trough). Plus, you may need to copy it over again after each modification of important/participating files. Alternatively (the best) -- try disabling such caching.