The rules and international phone number validation vary significantly across the world. The most common format is the country code + digits, but there are also a lot of variations with different digit lengths, starting with an international call prefix like 0 or 1, and so on. It is therefore difficult to validate a phone number input when the format does not follow a fixed standard.

Luckily, there is a simple industry-standard notation defined in E.164 that can be easily applied. Using a WPF textbox, it is possible to validate phone numbers by checking whether or not the number starts with ‘+’, ‘0’ or ’00’, removes these and any other special characters, checks the maximum length of the country code, and ensures that the final digits are valid. This article describes how to achieve this using the WPF framework and shows an example with production quality code that you can use in your web application.

Carrier Lookup APIs: Identifying Telecom Providers

In addition to phone number validation, the service offers more advanced validations including identifying mobile or landline status and indicating line type (fixed or wireless). The API can be integrated seamlessly into your online forms to improve user experience and reduce fraud with real-time validation at the point of data entry.

Check out the API’s docs and try it out now to get started!