[m33k44]

Well, I am not a web developer; thought I have developed simple web apps for understanding the development process but never deployed anything in the wild. My experience is into embedded and desktop application development. I recently received a request from one of my clients to develop a small web app that has to be accessible from the client's multiple offices with 3K employees. The employees use varying devices and web browsers (e.g. IE8+, old Android and iOS phones etc). I am looking for information on what things I should look for, from deployment, security and maintanibility point of view, before, during and after deploying the software. The web app is a simple work log book where employees log in the tasks done everyday and supervisors audit the information entered.

I want this web app to be secure, scalable and maintainable. If the client in future wants someone else to take over the project then it has to be easy for them to do so.