Hi, I am in the process of building a new app. The app allows users to signup with their mobile number (including the country prefix), which they then verify with a SMS. When the user has signed up, the app checks the users contacts in their phonebook to see which of their contacts is already signed up and using the app too. It then adds each of these contact to a Friends list. I have a big problem which i can't seem to get my head around: Most mobile numbers start with a 0 when they are used within their own country, such as 087 123 4567 for Ireland... however each country also has their own country prefix, such as +353 for Ireland, and when we use the prefix code, we usually drop the 0, such as +353 87 123 4567 As i mentioned above, the app uses the mobile number as your unique identifier and checks to see which of your friends are already using the app. Some users will have their friends saved as 087 333 4444 and others will have them saved with the country prefix +353 87 333 4444 and therefore the app will not recognise the simple version of 087 333 4444 Can anyone think of a way of resolving this? Thanks in advance for your help.