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Factline Phone Number Validation
x402
Factline Phone Number Validation is a paid API for AI agents from factline.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-11).
Validates and formats a phone number for any country, returning line type, E.164/national/international formats, calling code, and SMS capability
Price / call$0.003
Success—
StatusUnknown
How this service works
API and MCP servers that let AI agents and apps check people, companies, Dutch addresses and cars against official records: sanctions and PEP lists, 10 company registers, Dutch property, rent and RDW vehicle data. From $0.001 per call.
Output
A JSON object containing: the input number, E.164/national/international formatted versions, calling code, ISO country code and country name, boolean valid and possible flags, line type (mobile, landline, VoIP, toll-free, premium rate, or shared cost), sms_capable boolean hint, data source attribution, and human-readable explanations for the valid and line_type fields.
Example use cases
Signup form phone verification
“Before creating this user account, check if the phone number they entered — 0612345678 with country NL — is a valid mobile number that can receive SMS for two-factor authentication.”
CRM contact data cleanup
“I have a list of customer phone numbers in various formats; start with +447911123456 and tell me if it's valid, what line type it is, and give me the clean E.164 version for our CRM.”
KYC onboarding phone check
“As part of KYC for this new user, verify that the phone number +4915212345678 is a real, possible German number, tell me if it's mobile or landline, and whether we can send them an SMS verification code.”
Technical details
Endpoint
GEThttps://factline.dev/v1/phone/verify?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need fast, globally applicable phone number validation with rich metadata (line type, SMS capability, multi-format output) powered by Google libphonenumber — ideal for signup flows, KYC pipelines, CRM cleanup, or SMS/calling agents where knowing mobile vs. landline vs. VoIP matters. Prefer it over regex-only validators or carrier lookup services when you need format normalization and line type classification in a single call without a separate carrier API.
Side effects
- Invalid or unparseable phone number returns valid:false and possible:false
- National number submitted without a country parameter may fail to parse
- Non-existent or unallocated number range returns possible:false
- Ported numbers may show original range type rather than actual carrier
- Missing required phone query parameter returns an error
- Rate limiting or payment failure (x402) blocks the request
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"e164": "+31612345678",
"input": "+31612345678",
"valid": true,
"source": "Google libphonenumber metadata",
"country": "NL",
"explain": {
"valid": "The number matches an allocated number range for its country (not whether it is currently in service).",
"line_type": "From the number range. Ported numbers keep their range type; carrier is not reported."
},
"national": "06 12345678",
"possible": true,
"line_type": "mobile",
"sms_capable": true,
"calling_code": "+31",
"country_name": "Netherlands",
"international": "+31 6 12345678"
}
}Tags
x402
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