PHP Bug Lost is a “one file script” for PHP debugging and monitoring, PBL is a free and open source script for debug PHP code.
It’s working by inserting a script (function) inside web pages and displays the information in a console window right over the web page.
The script can present custom logs, SQL queries, variables, Ajax queries and measure loading times + CPU/memory usage.

PHP Bug Lost is not only built to be used in the development environment but it can also be set to auto-send e-mails when any of the monitored data is over or below the expected values.
Website: http://pbl.elgatonaranja.com/
Demo: http://pbl.elgatonaranja.com/demo