Hi,

I want to create a form on my website using C#.

1. After the user submits the form I want to use the API to check if a contact exists using that email address. 

2. If the contact exists I want to update the contact.

3. If the contact does not exist I want to check if a lead exists for the email address.

4. If a lead exists I want to update the lead.

5. If the lead does not exist I want to insert a lead.

Is this possible to do using the API?

Any code samples in C# of people using the API on websites would be greatly appreciated.