While we provide access to virtual numbers in many countries, Nexmo does not directly provide a web interface for receiving your inbound SMS.
You can use the Nexmo API to build your own web tool by building a script that would process the GET (default) request that we would send to your inbound webhook URL for each inbound SMS. You can find the details of the parameters we send to you here.
Alternatively, Nexmo has partnered with Telerivet, which provides a web app that makes it easy to send and receive SMS messages via Nexmo from any web browser. To get started, visit https://telerivet.com/nexmo, create an account on Telerivet, and follow the steps to connect your Nexmo account.