Phone intelligence API

Updated 2026-09-29

Everything a phone number can tell you before you trust it: whether it is real and dialable, who carries it, whether it was made in an app, whether its SIM just moved, which accounts are linked to it - and a risk score that says why.

One call

POST /v2/phone
curl -X POST "https://api.digifootprint.dev/v2/phone" \
  -H "Authorization: Bearer dfp_your_key" \
  -H "Content-Type: application/json" \
  -d '{"phone": "+14155552671", "checks": {"riskSignals": true}}'
200 OK
{
  "lookupId": "aaf935d9-...",
  "phone": {
    "number": "+14155552671",
    "valid": true,
    "e164": "+14155552671",
    "nationalFormat": "(415) 555-2671",
    "countryCode": "US",
    "carrier": "Bandwidth.com",
    "lineType": "nonFixedVoip",
    "isVoip": true,
    "voipClass": "nonFixed",
    "simSwap": null,
    "risk": {
      "score": 25,
      "signals": [
        { "id": "phone.internet_number", "label": "Internet (VOIP) number", "points": 15, "severity": "medium" },
        { "id": "phone.unanchored_voip", "label": "VOIP number anyone can create in an app", "points": 10, "severity": "medium" }
      ]
    }
  }
}

What comes back

Validity and formats from the numbering plan itself: whether the number is a real allocated range, its E.164 and national form, country and calling code. Carrier and line type from carrier data, with isVoip as the shorthand and voipClass as the signal - fixed VOIP is a business line, non-fixed VOIP is the throwaway kind. SIM-swap and call-forwarding risk detection on higher plans.

Digital Footprint analyses phone numbers for risk. We do not provide calling, SMS, SIM or any telecom service.

Add the footprint to the same request (POST /v2/lookup with a phone) to see which platforms have an account for the number. A number with no accounts anywhere is itself a signal.

Unknown is never no. A field no source could answer is null, not false - so a missing SIM-swap check never reads as “safe”.

Frequently asked questions

What API tells me if a phone number is VOIP or a real mobile?
The Digital Footprint phone intelligence API returns the line type and a voipClass that separates fixed VOIP (a business line tied to an address) from non-fixed VOIP (a number anyone can create in an app) - the category that shows up in signup fraud.
Can I find out which accounts are linked to a phone number?
Yes. The same lookup can run the social footprint on the number, reporting which platforms such as WhatsApp and Telegram have an account for it - verified, or left out, never guessed.
Does the phone API detect SIM swaps?
SIM-swap and call-forwarding risk detection are available on the Scale plan and above, where the carrier supports them. Where they are not available the fields are null, never false.
What is a phone number validation API?
A phone number validation API confirms that a number is real and dialable before you trust it: whether it belongs to an allocated range, its correct E.164 and national format, its country, carrier and line type. The Digital Footprint phone API adds VOIP detection and a risk score to the same answer.
Can the phone API check whether a number is on WhatsApp or Telegram?
Yes. Add the phone footprint to the same request and the number is checked on WhatsApp and Telegram by default, and on Facebook, Instagram and X on request. Each platform is priced separately and billed only when it runs.
How much does a phone check cost?
Each plan has a per-check phone price shown on the pricing page, and pay as you go charges a flat price per lookup with no subscription.

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