Q:

is developing an HTML web app using Notepad++ secure

I have started on a web app for the ORG i work for, using notepad++ for html and css and of course php and javascript. I must say that the ORG did not used to have software developers, all software they have is off-the-shelf or oracle forms and am a recent grad. 
We got a new hire he has much more experience "he claims", the thing is that he has been criticizing me for using notepad++ for html, he instead suggests using ASP.NET in VS. His argument comes from security risks and better support point of view.
The web app will consist of a website for the visitors to browse, in addition to an intranet for employees to use onsite and globally.
So i am not sure if i am on the right track and he is showing off, or i should be following his advice "he could be our new IT manager".
I thank you very much in advance.

A:

The editor you are using has literally nothing to do with the security of the programmed application. Notepad++ is perfectly fine, even though i would recommend something like Atom, Visual Studio Code or Sublime.
One thing they have as a "security advantage" over Notepad++ is, that it is easier to install plugins that try to check your code and point out possible bugs. Otherwise blaming the Editor for Security issues is nonsense.
I have no experience with ASP.NET, i tried it a few times but never liked it. I think it comes with some authentication solutions out of the box.
HTML and CSS have very little to do with security. JavaScript and especially PHP is what you have to be careful with. I would recommend to use some kind of PHP framework as there are often well tested authentication components included. Frameworks I know of are Symfony and Laravel (which is built on Symfony).

