I wrote the Catmail Opt-In application using the Zend Framework. This was my first opportunity to build a production application with the framework, and it worked out great. The actual opperations that the application performed were pretty simple. The challenging part was figuring out all the places where things could go wrong. The Opt-In application was the controller between several different systems, each one of which had its own interface and could present its own errors. Each of these potential error cases had to be identified, and dealt with — either try and correct the problem if we could, or present it to the client in a friendly and helpful manner.

Over the course of a few months, we migrated thousands of students to Google for email. There were some problems, both on our end and Google's. The Opt-In application was able to display the current states and statuses of each student's migration progress, and helped to make a complex transfer work remarkably well.