One of the most convenient features of the CLI is the ability to quickly direct Twilio webhooks to a new handler. Both Incoming Message Webhooks and Voice are supported.
For example, you can redirect incoming SMS webhooks to the /handle-sms route of your deployed server with:
1twilio phone-numbers:update {PHONE_NUMBER_SID|E164} \2--sms-url http://www.your-server.com/handle-sms
Replace {PHONE_NUMBER_SID|E164} with either the SID of your Twilio number (ex. PNXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX), or the E.164 formatted version of the phone number itself (ex. "+14155552671"). This will set the primary SMS URL for the given Twilio Phone number, and that endpoint will begin handling incoming messages.
Similarly, you can leverage the --voice-url flag to modify your phone number's incoming call handler:
1twilio phone-numbers:update {PHONE_NUMBER_SID|E164} \2--voice-url http://www.your-server.com/handle-call
There are also options for setting the fallback URL and more. Run twilio phone-numbers:update --help for a full list of options.
If you specify a webhook URL that uses the host name localhost or 127.0.0.1, the CLI will automatically create a public proxy for you using ngrok and set your webhook to direct requests to the new proxy URL. For example:
1twilio phone-numbers:update {PHONE_NUMBER_SID|E164} \2--sms-url http://localhost:3000/handle-sms
This is incredibly handy when trying to prototype an application and validate your webhook handler logic without deploying code to a publicly accessible URL.
Please be aware that this will temporarily expose your computer to the internet. You should exit this command when you have completed testing.
In addition to these built-in features, Twilio Labs has released a CLI plugin to further help you develop and test your webhooks: the Webhook plugin for the Twilio CLI.
Read this excellent introduction blog post to learn more.