As far as GitHub, that’s a good idea. But I think I’m going to pass on it (for now) mainly because the linked QuickStart page has all of the code to get a sample VM system running. In the post, I highlighted what code I removed and then added for the VM notification. Actually going through the QuickStart code step by step taught me a lot, so I recommend folks start there. Additionally, they’ll need the code to reflect their own Twilio credentials and phones numbers. Thanks!
Many businesses try to save money by selecting an amateur voice actor from inside the company to provide a recording. The trouble with this is that: The “actor” is typically an amateur with no voiceover experience. The company doesn’t have personnel with directing voiceover. The “actor’s” goal is to finish quickly and get back to work, not make the best-quality recording.

If you want them to leave a voicemail, tell them right from the beginning, “Please leave your name, reason your calling, and the best way to contact you.” If you want them to call you back during normal business hours, tell them, “Please call back during normal business hours.” If you want them to call back prepared for a lengthy conversation, you can say something like, “Please refer to our website’s FAQ page,” and then provide the URL. Self-service should never be underestimated.
There you have it! With an inexpensive Raspberry Pi, a little coding knowledge and effort, Twilio’s excellent APIs, documentation and Quickstart code, you can make your own voicemail server. For that matter, you can do a number of other things related to voice or message communications as well!