Learn About Phone Number Validity  

Introduction

Almost everyone has given out an incorrect phone number at some point, whether it's by mistake or on purpose. Ensuring that your users provide accurate contact details will allow them to receive and retrieve one-time passwords, receive important updates, and avoid wasting customer support time with unreachable numbers. Let's look at other use cases where verifying a phone number's validity matters. 

When referring to validity, it's essential to consider three key aspects: format validity, carrier-assigned validity, and reachability. The Identity Insights API checks a number across several validity dimensions.

Number Format Validity 

The Number Format Insight provides detailed insights into a phone number's structure and format validity, returns the country, prefix, and formatting information. It helps ensure compliance with international numbering standards.

There is inconsistent formatting across countries, difficulty validating phone numbers at scale, and a risk of processing invalid, incorrectly formatted, or ineligible numbers.

By using the Number Format, we can ensure numbers are compliant with global standards, reduce errors, and save time and money spent on customer onboarding and communication. It also improves efficiency by detecting invalid formats early, which in turn supports better routing and localization based on offline location and time zones.

Carrier Assigned Validity

Brands should avoid trusting non-mobile numbers when attempting to associate a phone number with an individual. You can check a carrier assigned validity by querying the current carrier for mobile numbers and the original carrier for others. Since the network type isn’t always known, checking the current carrier first is recommended. Calling an unassigned number can result in different outcomes, such as an unreachable message, an error tone, a carrier redirect, or no response, depending on the carrier and country.

Check how to make an API call that returns information about the network the phone number is currently assigned to, including the name, network type, and country code.

Reachability

Reachability defines whether a phone number can be contacted right now through calls, texts, or data. Even if a number looks valid and is assigned to a carrier, it doesn’t always mean you can reach it; sometimes the phone might be switched off or out of service. 

Note: The reachability capacity from Identity Insights will be available in the future. You can currently access the insight using the playground using the Virtual Operator only.

Use Cases

Validating phone numbers helps to prevent fraud, ensure accurate user input, clean data, and targeted marketing. It also enables geographic personalization, reducing errors and saving time and costs. Now, let’s explore some practical use cases.

Fraud Prevention

Reject impossible or non-compliant numbers to reduce your attack surface before sending one-time passwords. Invalid or impossible phone numbers can be identified and blocked early in the process, which prevents sending sensitive one-time passwords to incorrect or malicious inputs. Apply additional security measures if the phone number is not associated with a mobile carrier, as it cannot be linked to an individual.

Customer Onboarding

Validate the format during registration or before creating accounts, so that account verification occurs on a real device. Verifying phone number validity during registration or account creation helps confirm that the input is structurally correct, ensuring verification messages are sent to devices that likely exist.

Marketing and Notifications

Ensure only valid format numbers are targeted. Filtering phone numbers to include only those that match valid formats ensures that marketing messages and notifications are directed to legitimate contacts rather than malformed or fake numbers. Decide whether to use SMS or RCS when the phone number is assigned to a mobile carrier.

Geographic Personalization

Adjust send times according to the country or time zone hints for the number. Phone number formats often contain country codes or regional indicators, allowing for adjustments such as timing messages to fit local time zones or tailoring content based on location.

Data Cleansing

Transforming phone numbers into a standardized format, like E.164, provides consistency across databases and simplifies integration, analysis, and management of contact information.

Conclusion

Ensuring that phone numbers are correctly structured, compliant with international standards, and assigned to a carrier can help prevent fraud, improve data quality and cleansing, facilitate real-time validation at input, enable segmentation and localization, and optimize costs. Learn more about the Identity Insights API in the API Reference.