How are numbers validated?

Phone number validation works differently from country to country. Below are details of how it works for some of the most called-to countries in Europe.

Spain

When validating Spanish numbers, Outbound:

1. Confirms country code +34 or 0034
2. Requires exactly 9 digits
3. Ensures number starts with valid Spanish prefixes (6, 7, 8, 9, 5)
4. Classifies number type (mobile, fixed line, VOIP etc)

Denmark

For Denmark:

1. Confirms country code +45 or 0045
2. Requires exactly 8 digits
3. Validates against Danish allocated prefixes
4. Classifies number type (mobile, fixed line, VOIP etc)
5. Ensures region = DK through the +45 prefix

Sweden

For Sweden:

1. Detects and removes trunk prefix 0
2. Confirms country code +46
3. Validates variable length rules (between 7 and 13 numbers)
4. Checks allocated prefix ranges
5. Classifies number type accurately (mobile, fixed line, VOIP etc)

Finland

For Finland:

1. Removing trunk prefix 0 when parsing national format.
2. Confirming country code +358 or 00358.
3. Validating variable-length numbers (Finland does not have fixed length).
4. Checking prefix allocations:
5. • 04x, 05x → Mobile
   • 02, 03, 09 → Geographic
   • 0800 → Toll-free
5. Classifying number type accurately.

England

For England:

1. Removes trunk 0 when converting to E.164.
2. Confirms country code +44 or 0044.
3. Validates complex area code structures (2–5 digit area codes).
4. Checks major prefix ranges:
5. • 07 → Mobile
   • 01, 02 → Geographic
   • 0800, 0808 → Toll-free
   • 09 → Premium

Germany

For Germany:

1. Removes trunk prefix 0.
2. Confirms country code +49 or 0049.
3. Supports very wide length ranges.
4. Checks prefix allocations:
5. • 015, 016, 017 → Mobile
   • 030 → Berlin
   • 040 → Hamburg
   • 0800 → Toll-free
   • 0900 → Premium
5. Validates area-code-dependent lengths.

⚠️ Germany is one of the most variable numbering plans in Europe — strict validation depends heavily on metadata.

Netherlands

For Netherlands:

1. Removes trunk prefix 0.
2. Confirms country code +31 or 0031.
3. Enforces 9-digit national significant number.
4. Checks prefix allocation:
5. • 06 → Mobile
   • 010 → Rotterdam
   • 020 → Amsterdam
   • 0800 → Toll-free
   • 090x → Premium