I have a code written in C# I would like to use as the back-end of a site I'm building.
I would prefer not to build the site front-end in ASP.NET (which integrates nicely with C#), and to use PHP or Python instead. 
Is that reasonable? Should I re-consider using ASP.NET?
How can I achieve that?
Ugh, in normal instances, reading data with C# writing it to files and loading up with PHP sound slow, inefficient and down wright crazy. I believe these terms are being used wrongly.
Client Server - user machine - database great for private networks where you connect to the DB without going over the internet
vs n-Tier
Client - Browser programming html, css, javascript connects to middleware over the internet
Middleware - inside your firewall, connects browser to database could be called part of backend - php and C# are middleware languages
Database final (generally 3rd) tier
With php and c# you are creating multiple middleware layers
why why why would you do this for a web app pick one
now if you have a web app with PHP and sneakerware in house client server apps that are controlled ie shipping, accounting that are not exposed - maybe but you have added complexity that you would not need (generally)
Gary
Connecting C# Back-end with PHP frontend