appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*",
  "Kestrel": {
    "Endpoints": {
      "https": {
        "Url": "https://localhost:5001"
      },
      "http": {
        "Url": "http://localhost:5000"
      }
    }
  },
  "ReverseProxy": {
    "Routes": {
      "route1": {
        "ClusterId": "cluster1",
        "Match": {
          "Methods": [ "GET", "POST" ],
          "Hosts": [ "localhost" ],
          "Path": "/api/{**catch-all}"
        }
      },
      "route2": {
        "ClusterId": "cluster2",
        "Match": {
          "Path": "{**catch-all}"
        }
      }
    },
    "Clusters": {
      "cluster1": {
        "Destinations": {
          "cluster1/destination1": {
            // Following value will be found by regex and looked up as an environment variable
            "Address": "{{contoso}}"
          },
          "cluster1/destination2": {
            "Address": "https://bing.com/"
          }
        }
      },
      "cluster2": {
        "Destinations": {
          "cluster2/destination1": {
            "Address": "https://example.com/"
          }
        }
      }
    }
  }
}