Some services use non-geographic country codes

[roseline371277]

Pitfall: After the "phone number country code," the national number's length varies greatly by country. A number might be too short or too long for the specified country code.
Troubleshooting: Implement robust number validation libraries that know the expected national number lengths and formats for each "phone number country code." Provide immediate feedback to the user if the length is incorrect.
Dealing with Leading Zeros (Beyond Trunk Codes):

Pitfall: Some specific numbers might legitimately have dataset leading zeros after the country code or within the national number (e.g., some non-geographic numbers or very old fixed lines). However, most systems incorrectly strip leading zeros.
Troubleshooting: Use a sophisticated parsing library that understands the nuances of national numbering plans. While common trunk code '0's are stripped, other legitimate leading zeros must be preserved.
"Phone Number Country Code" for Non-Geographic Numbers (e.g., Satellite, Premium Rate):

Pitfall: (e.g., +882 for international networks, +870 for Inmarsat satellite phones). These can be confusing or incur very high costs.
Troubleshooting: Awareness is key. For businesses, clearly flag numbers with non-geographic country codes for cost implications or special routing.
Outdated Country Code Information:

Pitfall: While rare, country codes can occasionally change, or new ones can be assigned (e.g., due to country splits).
Troubleshooting: Rely on regularly updated phone number validation APIs and services that incorporate the latest ITU E.164 recommendations. Don't rely on static, manually updated lists.
Parsing from Free-Text Fields:

Pitfall: If users enter phone numbers into a single free-text field, extracting the correct "phone number country code" and the rest of the number can be challenging due to varying formats (e.g., spaces, dashes, parentheses).