User Experience
Users often prefer entering and seeing numbers in the familiar local format. An app targeting users in Bangladesh, for example, should ideally allow input like 01712-345678 instead of asking for +8801712345678.
2. Input Flexibility
Many libraries are designed to parse local phone number library formats effectively — as long as a default country or region is provided. This allows developers to support both local and international formats seamlessly.
3. Region-Specific Formatting
Local formatting enhances readability. For example, (03) 9876 5432 is more readable to Australians than +61398765432. Libraries like libphonenumber offer display functions like formatNational() to present numbers according to regional conventions.
Best Practices: Leveraging Libraries for Format Management
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Store in International Format, Display in Local Format
The ideal approach is to store all numbers in international (E.164) format for consistency and interoperability, and display them in local format based on user region or locale. -
Use Libraries for Parsing and Formatting
Use robust libraries (e.g., libphonenumber, PhoneNumberKit, phonenumbers.js) to parse user input, normalize numbers, and apply appropriate validation rules. They can also detect whether a number is possible, valid, or correctly formatted. -
Ask for Country or Use Region Hints
To accurately parse a local but the mobile app doesn’t get all the attention number, libraries often need a default region. Always prompt the user for their country or infer it via geolocation to ensure correct parsing. -
Normalize Early in the Workflow
Normalize numbers as early as possible in your data pipeline — ideally at the input stage — to ensure your system works consistently across all use cases.
Conclusion
Choosing between local and international phone number formats is not a matter of preference, but of context and design strategy. International formats provide a standardized, machine-friendly representation perfect for storage and API interactions. Local formats offer better user experience and readability.
Phone number libraries bridge the gap between lack data these formats, enabling developers to build systems that are both user-friendly and globally compatible. With proper use of these tools, it’s entirely possible to support the best of both worlds — clean data for machines and familiar experiences for humans.