What types of numbers does Twilio offer and how do they work?
Geographic numbers are telephone numbers which are assigned to a specific region. In the US and Canada these regions are represented by area codes. Outside the US and Canada these regions map to a range of numbers which could be a province, state, city or neighborhood.
National numbers are telephone numbers which are not region-specific. These are phone number ranges designated to be reachable from an entire country.
Placing calls into national Twilio numbers is often charged by the calling carrier the same way a local call would be charged. However, this varies based on the carrier initiating the call (i.e. the mobile carrier of the incoming caller). To be sure of the charge that will be incurred to call into a Twilio national number, you should speak with your carrier.