For fintech and lending onboarding
Check the phone number on every application before you send the one-time code: mobile, landline or VoIP from a live carrier dip, whether a carrier deactivated it in the last 45 days, and whether it is on our internal blacklist. They are fraud-scoring inputs for your risk model, not identity verification.
| Number | The lookup says | Do this |
|---|---|---|
| (646) 555-0125 | Active mobile | Send the code |
| (415) 555-0163 | VoIP line | Step-up review |
| (702) 555-0118 | Deactivated by the carrier Oct 3 | Ask for another |
| (305) 555-0172 | On our blacklist | Manual review |
| (312) 555-0144 | Landline, can't get an SMS code | Ask for a mobile |
Fictional 555 numbers.
No. The bank CIP rule's minimum identifying information is name, date of birth, address and an identification number. Phone signals sit alongside it as fraud-scoring inputs.
31 CFR 1020.220(a)(2)(i)(A) · ecfr.gov
nanpTypedipCarrierSubType dipCarrierSubType "IPES" marks an IP-enabled (VoIP) line, from a live carrier dip. VoIP isn't fraud by itself; weigh it with your other signals.
dipCarrierSubType = IPES deactivationDate shows a carrier deactivation in the last 45 days, and reason carries the carrier id and date. Don't spend a one-time code on it.
deactivationDatereason About 32% of the numbers we look up are landline or VoIP. Check the line type before you pay for the SMS.
Source: CheckThatPhone lookup data
nanpTypedipCarrierTypeaction Call the API the moment the applicant enters a phone number, before you pay to send an SMS code. Ask for another number when it was deactivated or can't take a text; for borderline cases, still send the code but flag the application for a stronger verification path downstream.
Feed the fields into your risk model as inputs: for example, points for dipCarrierSubType "IPES", a deactivationDate or blackList: "true". Approve, step up or route to manual review, with weights and thresholds tuned on your own outcomes.
After you change your rules, run the numbers on existing accounts through a CSV upload and send high-risk accounts to fraud ops. Compare dipCarrier and dipOcn with what you stored at signup to see a carrier change since.
None of these is decisive on its own. They are inputs to your scorecard; the approve-or-decline call is yours.
| If the response shows | Field | Do this |
|---|---|---|
| Active mobile | action = sendnanpType = mobile | Send the SMS code. |
| VoIP | dipCarrierSubType = IPES | A risk input: weigh it with your other signals, and consider step-up verification. |
| Deactivated by the carrier recently | deactivationDatereason | Don't send the code. Ask for a working number. |
| On our internal blacklist | blackListreason | Route to manual review. reason reads "Blacklisted Subscriber". |
| Landline | nanpTypedipCarrierType | It can't take the SMS code, unless the landline SMS check returns smsEligible: "true". Offer another channel or ask for a mobile. |
| A different carrier than at signup | dipCarrierdipOcndipLrn | The number has likely been ported since you last checked. Consider a step-up challenge before a sensitive action. |
| Ported | dipPorted | Not a recency signal: it has no date. Compare carrier fields over time instead. |
| Applicant location | geoStategeoSourceipResult | With an ip passed, location comes from the IP; without one, from the area code. One call returns one or the other, so it cannot compare them. ipResult only says the IP was valid. |
An active mobile on a wireless carrier, not blacklisted, no recent deactivation. The applicant's IP was passed, so location and time zone come from the IP (geoSource: "ip"); ipResult only says the IP was valid.
Highlighted fields: action, blackList, dipCarrierSubType, dipCarrierType, geoSource.
{
"success": true,
"credits_used": 1,
"data": {
"subscriber": "6465550125",
"optDate": "2026-10-08T21:56:26.108Z",
"action": "send",
"deliverable": "true",
"nanpType": "mobile",
"blackList": "false",
"ipResult": "valid-v4",
"dip": "success",
"dipLrn": "6465550125",
"dipPorted": "false",
"dipOcn": "6010",
"dipCarrierSubType": "WIRELESS",
"dipCarrier": "AT&T",
"dipCarrierType": "mobile",
"geoState": "NY",
"geoCity": "New York",
"geoCountry": "US",
"geoMetro": 501,
"timezone": "America/New_York",
"tzOffset": 5,
"geoSource": "ip",
"error": "false",
"smsEligible": "true"
}
}Monthly cost:
A plain lookup, no add-ons needed for these signals. Computed from the published plans. The free plan's 500 lookups a month cover pre-launch testing.
IPESaction) before you send a codeNot legal advice.
dipPorted says a number moved carriers at some point. It has no date, so it is not a recent-port or SIM-swap signal.deactivationDate: data refreshed daily, with a 1 to 7 day lag, and entries expire after 45 days. It is not a reassigned-number check.ip passed, location and time zone come from the IP, otherwise from the area code. One call can't compare the two.No. Phone signals are a fast first-pass filter that runs before you spend on document verification. Use them to decide whether to challenge a signup, route it to manual review, or let it proceed.
Not under the bank CIP rule, whose minimum identifying information is name, date of birth, address and an identification number (31 CFR 1020.220(a)(2)(i)(A)). Treat phone signals as fraud-scoring inputs alongside your CIP, not as CIP verification. This page is not legal advice.
Nothing. ipResult only says whether the IP you passed is valid ("valid-v4" or "valid-v6"). When you pass an IP, geoState, geoCity and timezone come from the IP (geoSource: "ip"); without one they come from the area code. One call returns one or the other, so it cannot compare the IP's location with the area code's.
dipCarrierSubType returns "IPES" (IP-enabled service) for VoIP lines. Mobile carriers return "WIRELESS" or "PCS"; wireline carriers return codes such as "ILEC", "RBOC" or "CLEC".
No. dipPorted says the number was ported at some point, with no date. To spot a carrier change, store dipCarrier and dipOcn at signup and compare them on a fresh lookup before a sensitive action.
500 free lookups a month for pre-launch testing. One credit per lookup after that.