# Factline Phone Number Validation

> 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

## Facts

- Endpoint: GET https://factline.dev/v1/phone/verify?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/factline-phone-number-validation-cd9ccb16
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_E436lE0FNeqAdS6zGzHR5

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability factline-phone-number-validation-cd9ccb16
```

Example prompt: Can you verify whether +31612345678 is a valid, SMS-capable mobile number and give me its properly formatted E.164 and national forms?

## When to prefer this

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.

## Known failure modes

- 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

## 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.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "phone"
     ],
     "properties": {
      "phone": {
       "type": "string",
       "description": "Phone number, international (+31612345678) or national with country, e.g. 0612345678"
      },
      "country": {
       "type": "string",
       "description": "Optional ISO country for national numbers, e.g. NL, DE, GB"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "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"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/factline-phone-number-validation-cd9ccb16/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from factline.dev](https://www.zero.xyz/host/factline.dev/llms.txt)