host.json

{
  "version": "2.0",
  "logging": {
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": true,
        "excludedTypes": "Request"
      }
    }
  },
  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle",
    "version": "[4.*, 5.0.0)"
  },
  "extensions": {
    "http": {
      "routePrefix": "api",
      "cors": {
        "supportCredentials": false,
        "allowedOrigins": [
          "http://localhost:3000",
          "https://localhost:3000"
        ],
        "allowedMethods": [
          "GET",
          "POST",
          "OPTIONS"
        ],
        "allowedHeaders": [
          "Content-Type",
          "Authorization",
          "Accept",
          "Origin"
        ],
        "maxAge": 86400
      }
    }
  }
}