Which versions of node.js are available on Azure Web Sites?

1. Open Advanced Tools (Kudu):

   

2. In Kudu, click on Runtime versions:

   

At the time of writing (August 2017), you'll see something like this:

{  "nodejs": [    {      "version": "0.10.18",      "npm": "1.4.28"    },    {      "version": "0.10.21",      "npm": "1.3.11"    },    {      "version": "0.10.24",      "npm": "1.4.28"    },    {      "version": "0.10.26",      "npm": "1.4.28"    },    {      "version": "0.10.28",      "npm": "1.4.9"    },    {      "version": "0.10.29",      "npm": "1.4.10"    },    {      "version": "0.10.31",      "npm": "1.4.28"    },    {      "version": "0.10.32",      "npm": "1.4.28"    },    {      "version": "0.10.40",      "npm": "1.4.28"    },    {      "version": "0.10.5",      "npm": "1.2.18"    },    {      "version": "0.12.0",      "npm": "2.11.2"    },    {      "version": "0.12.2",      "npm": "2.11.2"    },    {      "version": "0.12.3",      "npm": "2.11.2"    },    {      "version": "0.12.6",      "npm": "2.11.2"    },    {      "version": "0.6.20",      "npm": "1.1.37"    },    {      "version": "0.8.19",      "npm": "1.2.30"    },    {      "version": "0.8.2",      "npm": "1.1.36"    },    {      "version": "0.8.26",      "npm": "1.2.30"    },    {      "version": "0.8.27",      "npm": "1.2.30"    },    {      "version": "0.8.28",      "npm": "1.2.30"    },    {      "version": "4.0.0",      "npm": "2.14.2"    },    {      "version": "4.1.0",      "npm": "2.14.4"    },    {      "version": "4.1.2",      "npm": "2.14.4"    },    {      "version": "4.2.1",      "npm": "3.3.9"    },    {      "version": "4.2.2",      "npm": "3.3.12"    },    {      "version": "4.2.3",      "npm": "3.5.1"    },    {      "version": "4.2.4",      "npm": "2.14.12"    },    {      "version": "4.3.0",      "npm": "2.14.12"    },    {      "version": "4.3.2",      "npm": "2.14.12"    },    {      "version": "4.4.0",      "npm": "2.15.8"    },    {      "version": "4.4.1",      "npm": "2.15.8"    },    {      "version": "4.4.6",      "npm": "2.15.8"    },    {      "version": "4.4.7",      "npm": "2.15.8"    },    {      "version": "4.5.0",      "npm": "2.15.9"    },    {      "version": "4.6.0",      "npm": "2.15.9"    },    {      "version": "4.6.1",      "npm": "2.15.9"    },    {      "version": "4.8.4",      "npm": "2.15.11"    },    {      "version": "5.0.0",      "npm": "3.3.9"    },    {      "version": "5.1.1",      "npm": "3.3.12"    },    {      "version": "5.3.0",      "npm": "3.3.12"    },    {      "version": "5.4.0",      "npm": "3.3.12"    },    {      "version": "5.5.0",      "npm": "3.3.12"    },    {      "version": "5.6.0",      "npm": "3.6.0"    },    {      "version": "5.7.0",      "npm": "3.6.0"    },    {      "version": "5.7.1",      "npm": "3.6.0"    },    {      "version": "5.8.0",      "npm": "3.7.3"    },    {      "version": "5.9.1",      "npm": "3.7.3"    },    {      "version": "6.0.0",      "npm": "3.8.6"    },    {      "version": "6.1.0",      "npm": "3.8.6"    },    {      "version": "6.10.0",      "npm": "3.10.10"    },    {      "version": "6.11.1",      "npm": "3.10.10"    },    {      "version": "6.2.2",      "npm": "3.9.5"    },    {      "version": "6.3.0",      "npm": "3.10.3"    },    {      "version": "6.5.0",      "npm": "3.10.3"    },    {      "version": "6.6.0",      "npm": "3.10.3"    },    {      "version": "6.7.0",      "npm": "3.10.3"    },    {      "version": "6.9.0",      "npm": "3.10.8"    },    {      "version": "6.9.1",      "npm": "3.10.8"    },    {      "version": "6.9.2",      "npm": "3.10.9"    },    {      "version": "6.9.4",      "npm": "3.10.10"    },    {      "version": "6.9.5",      "npm": "3.10.10"    },    {      "version": "7.0.0",      "npm": "3.10.8"    },    {      "version": "7.1.0",      "npm": "3.10.9"    },    {      "version": "7.10.0",      "npm": "4.2.0"    },    {      "version": "7.10.1",      "npm": "4.2.0"    },    {      "version": "7.2.0",      "npm": "3.10.9"    },    {      "version": "7.3.0",      "npm": "3.10.10"    },    {      "version": "7.4.0",      "npm": "4.0.5"    },    {      "version": "7.5.0",      "npm": "4.1.2"    },    {      "version": "7.6.0",      "npm": "4.1.2"    },    {      "version": "7.7.4",      "npm": "4.1.2"    },    {      "version": "8.0.0",      "npm": "5.0.0"    },    {      "version": "8.1.4",      "npm": "5.0.3"    }  ]}

Credit goes to this blog post and this answer for showing me how to do it.

Using the Azure CLI is easiest:

az webapp list-runtimes

returns:

[  "aspnet|v4.7",  "aspnet|v3.5",  "node|0.6",  "node|0.8",  "node|0.10",  "node|0.12",  "node|4.8",  "node|6.12",  "node|7.10",  "node|8.4",  "node|8.5",  "node|8.9",  "node|8.10",  "node|8.11",  "node|10.0",  "node|10.6",  "php|5.6",  "php|7.0",  "php|7.1",  "php|7.2",  "python|2.7",  "python|3.4",  "java|1.7|Tomcat|7.0",  "java|1.7|Tomcat|8.0",  "java|1.7|Tomcat|8.5",  "java|1.7|Tomcat|9.0",  "java|1.7|Jetty|9.1",  "java|1.7|Jetty|9.3",  "java|1.8|Tomcat|7.0",  "java|1.8|Tomcat|8.0",  "java|1.8|Tomcat|8.5",  "java|1.8|Tomcat|9.0",  "java|1.8|Jetty|9.1",  "java|1.8|Jetty|9.3"]

Available WEBSITE_NODE_DEFAULT_VERSION options can found here:

https://[your app name].scm.azurewebsites.net/api/diagnostics/runtime

For more details check How to find available node.js versions for Windows Webapps.