title: SignalR Service (Serverless) - Azure Functions
body: <p>I am confused about SignalR, specifically when using the Azure SignalR Service and then even more so when thinking about the server-less implementation using Azure Functions.</p>
  
  <p>I have a web app and an Azure Function app, which has a negotiation function implemented. The JavaScript on the client is successfully negotiating and able to connect to the Azure SignalR Service, so far so good. </p>
  
  <p>Side question: <strong>Is the only thing that stops any old person connecting and getting a token the CORS setting? Is this secure enough on its own?</strong></p>
  
  <p>After this is where I get confused. I now have a Azure SignalR Service and an Azure Function app, what use does the Function App serve after the client connection to the Azure SignalR Service has been established? </p>
  
  <p>In terms of client interaction I need to do things like join a group and broadcast to said group (from JavaScript on the client), <strong>I assume those would be two additional functions (Http triggers) on the function app?</strong></p>
  
  <p>Assuming I am correct on the above, <strong>how do I stop anyone from calling the 'broadcast' function via the function apps http endpoint</strong>? At least locally I am able to call it from Postman without providing any information received in the initial negotiate response.</p>
  
  <p>I also need to push messages to groups from backend code (.net standard), <strong>is this done by a call to the function app or straight to the Azure SignalR Service?</strong> </p>
  
  <p>Thanks in advance.</p>