The prefix or range a phone number is in typically signifies the type of phone number it is. Phone number type often implies several characteristics about a phone number including:
- The caller’s cost to dial the number (which can be significantly higher for mobile numbers)
- The expected user that will be reached the other end of the phone number (a business, an individual on a mobile phone, or someone on their landline)
- Capabilities of a given phone number (mobile numbers can receive messages whereas other types of numbers typically cannot receive messages)
- The location of a given phone number
The following are the types of phone numbers Twilio provides:
Local numbers are telephone numbers which are assigned to a specific region. These numbers are typically used by individuals, local businesses and can be considered the most general type of numbers. In the US and Canada, these regions are represented by area codes. For example, +1 (415) XXX-XXXX numbers are located in the San Francisco Bay Area.
Outside the US and Canada, phone numbers are mapped in ranges to a specific region. Ranges can vary in length between 1 and up to 6 digits of the phone number. For example, a +44 20 XXXX XXXX number is located in London while a +44 151 XXX XXX number is located in Liverpool, UK.
National numbers are telephone numbers which are not region-specific and were designed to be reachable from an entire country at the same cost. This type of number is more common outside the US and Canada and are generally used for larger businesses that want to easily be reached from around the country. Since national phone numbers are not tied to a particular local area, the geodata for a national number is listed as the country.
The cost for your user to call a national number is often regulated and priced the same as a local call. However, this varies based on the carrier initiating the call (i.e. the mobile carrier of the incoming caller, or the provider of the user’s local phone service) and the regulations of each country. In some countries, national numbers can only be reached from within the country, although this varies based on the network of the phone provider and country from which a national number is being dialed.
Toll free numbers
Toll free numbers are telephone numbers that are free of charge for the calling party, and are typically used by businesses when they prefer fully take on the cost of calls for their users. Similar to a geographic area code, toll free numbers are organized in ranges such as +1 888 XXX-XXXX in the US and Canada and +44 800 XXX XXXX in the U.K.. Twilio currently provides toll free numbers in United States, Canada and United Kingdom. In the United States and Canada, toll-free numbers are enabled for both voice and SMS messaging. Toll-free numbers in the United Kingdom cannot yet be used to send messages.
In most countries, mobile numbers are assigned to a particular range within the country’s telephone numbering plan so they can be easily distinguished from local numbers. They are often the only type of number in the given country that can be used for sending and receiving messages.