Magento supports a developer mode.
The developer mode is intended to be used and useful during development.
Particalary, Magento in developer mode shows exceptons on screen instead of showing a generic error message like "There has been an error processing your request".
How to enable the developer mode
Magento 1.x
Set the webserver environment variable MAGE_IS_DEVELOPER_MODE to any value, for example:
Listen 807
<VirtualHost 127.0.0.1:807>
ServerName localhost.com
DocumentRoot "C:/work/magento/1.9.2.0-rm3/code"
SetEnv MAGE_IS_DEVELOPER_MODE "any value"
SetEnv RM_DEVELOPER "1"
</VirtualHost>
Magento 2
Set the webserver environment variable MAGE_MODE to the value developer.
An example for Apache:
Listen 1900
<VirtualHost 127.0.0.1:1900>
ServerName localhost.com
DocumentRoot "C:/work/mage2.pro"
SetEnv MAGE_MODE "developer"
SetEnv MAGE_RUN_TYPE "website"
SetEnv MAGE_RUN_CODE "mage2_pro"
RemoteIPHeader X-Forwarded-For
</VirtualHost>
An example for Nginx:
location ~ \.php$ {
fastcgi_param MAGE_MODE "developer";
}
Since 2015-08-24 the developer mode can also be enabled from the command line:
bin/magento deploy:mode:set developer