Phone Validation API

This API validates, normalises, and enriches phone numbers in real time to ensure high data quality across online forms, CRMs, and internal workflows. It converts raw inputs into the standard E.164 format while extracting critical metadata, including country of origin, location, line type (e.g., mobile or landline), and carrier network where available. By assessing multiple real-time signals, the API delivers a definitive usability status to help systems automatically filter out invalid entries and maintain a clean contact database.

Download Full API Specification (PDF)

Download OAS OpenAPI Specification (YAML)

Endpoint

Method	URL
POST	https://api.data-checks.com/v1/phone

Request body (JSON)

Field	Meaning
phone	Number to validate. Spaces, +, brackets, and dashes are accepted.
iso_country	Default country code (2-letter). Used only if the number lacks a + prefix. Defaults to GB if omitted.

Request example

POST https://api.data-checks.com/v1/phone
Authorization: Bearer <YOUR_API_KEY>
Content-Type: application/json

{
  "phone": "07123 456789",
  "iso_country": "GB"
}

Successful response - HTTP status 200

Field	Meaning
input	Original submitted value.
normalized	Canonical form. E.164 standard.
is_valid	Whether the input is considered valid.
reason	The specific reason code explaining why the phone number is considered valid or invalid.
type	The type of phone number (e.g. Landline, Mobile, etc.).
provider	Network or service provider, when available.
location	Location associated with the number.
iso_country	ISO 3166-1 alpha-2 of the country.
remaining_credits	Phone credits remaining after this validation.

Successful response example

HTTP/1.1 200 OK

{
  "input": "07123 456789",
  "normalized": "+447123456789",
  "is_valid": true,
  "reason": "active",
  "type": "Mobile",
  "provider": "Vodafone",
  "location": "United Kingdom",
  "iso_country": "GB",
  "remaining_credits": 99
}