# Voice REST API Tutorials

Learn how to apply the Voice REST API by following these tutorials:

| Tutorial | Description | Language |
|  --- | --- | --- |
| [Build your own conference calling system](/docs/voice/tutorials/build-your-own-conference-calling-system-in-c) | Learn how to build your own conference calling system. | ASP.NET |
| [Mask a number](/docs/voice/tutorials/number-masking) | Learn how to mask a number on an incoming call. | ASP.NET Core 6.0 |
| [Build a lead qualification app](/docs/voice/tutorials/qualify-leads) | Learn how to build an app that qualifies leads using AMD and IVR. | Java SDK |
| [Test Sinch callbacks](/docs/voice/tutorials/getting-a-second-number-and-testing-sinch-callbackswebhooks-with-ngrok) | Learn how to redirect a phone call to your number from a Sinch number using ngrok. | Node.js |