For affiliates, networks and lead buyers
Validate every lead inside the form-submit handler, before you ping a buyer: line type after porting, a carrier deactivation in the last 45 days, our internal blacklist and, with the litigator scrub, known TCPA litigators. The result travels with the ping, and buyers can re-check it on the post.
| Number | The lookup says | Do this |
|---|---|---|
| (602) 555-0114 | Mobile, not a known litigator | Ping all buyers |
| (818) 555-0137 | VoIP line | VoIP buyers only |
| (512) 555-0129 | Landline, can't take texts | Call buyers only |
| (212) 555-0147 | Known TCPA litigator | Discard |
| (305) 555-0161 | Deactivated by the carrier Oct 4 | Discard |
Fictional 555 numbers.
About 32% of the numbers we look up are landline or VoIP. If your buyers price by channel, nanpType and dipCarrierSubType belong in the ping.
Source: CheckThatPhone lookup data
nanpTypedipCarrierSubType Each call or text that breaks the TCPA rules on autodialed or prerecorded calls can cost $500 in statutory damages, and up to three times that if the court finds it willful or knowing.
47 U.S.C. 227(b)(3) · law.cornell.edu
litigatorlitigator_type The 11th Circuit vacated the FCC's one-to-one consent rule on January 24, 2025, before it took effect. Prior express written consent is still required for autodialed or prerecorded telemarketing.
Insurance Marketing Coalition v. FCC (11th Cir. 2025) · media.ca11.uscourts.gov
optDate timestamps every lookup, and deactivationDate and reason show whether the carrier had deactivated the number. Store the response with the lead for disputes; your contract decides the outcome.
optDatedeactivationDatereason The same pattern works for direct affiliate-to-advertiser flows and for ping-post platforms that broker leads between many sources and many buyers.
The seller's submit handler calls the API with litigatorFilter: true and stores the response on the lead. The visitor sees the thank-you page right away; the lookup runs server-side. A hard reject (deactivated, litigator, blacklisted) never enters the marketplace.
Include nanpType, dipCarrierType, dipCarrierSubType, dipPorted, geoState and optDate in the ping. Buyers' acceptance rules and bids run on that metadata.
Buyers call the API themselves on the post and compare it with the seller's claims. A mismatch (seller said mobile, buyer sees VoIP) feeds seller quality scoring. It is one more lookup per accepted lead.
Re-check recent leads weekly for active sources and monthly for archives. A number that was clean at submit but has since been deactivated or flagged tells the seller the source is going stale, and the buyer not to recontact.
Which buyer tier a lead fits, and whether it is sellable at all. Absent DNC fields mean the check didn't run (not checked), never clear.
| If the response shows | Field | Do this |
|---|---|---|
| A hard reject | action = unsubscribereason | Read reason first. A litigator match, "Blacklisted Subscriber" or a carrier deactivation means discard. "Not a valid mobile number" is a landline: still sellable to call buyers. |
| Known TCPA litigator | litigatorlitigator_typelitigator_name | Discard. Needs litigatorFilter: true (+1 credit per lookup). |
| On our internal blacklist | blackListreason | Hard reject. blackList is "true" for numbers on our internal blacklist of flagged numbers, and for any litigator match; reason and litigator tell you which. |
| Active mobile | nanpType = mobiledipCarrierSubType = WIRELESS | Premium tier: SMS and call buyers. |
| VoIP | dipCarrierSubType = IPES | Discount tier, or a buyer that specifically takes VoIP. |
| Landline | nanpTypedipCarrierType | Call-center buyers, not SMS buyers, unless the landline SMS check returns smsEligible: "true". |
| Deactivated by the carrier recently | deactivationDate | Discard: the carrier deactivated it in the last 45 days. |
| State DNC or complainer match (free) | dncStateResult = STATE DNCdncComplainerResult = DNC COMPLAINER | Pass it to buyers. Whether to call is their consent decision. If dncStateChecked is absent, the state was not checked. |
| State and time zone | geoStatetimezonegeoSource | For state-licensed buyers and call cadence. From the visitor's IP if you pass one, otherwise the area code; neither proves where the person lives. |
| Ported | dipPorted | Metadata only: the number moved carriers at some point. There is no port date. |
An active mobile on a wireless carrier, not a litigator, with the litigator scrub on. The visitor's IP was passed, so geoState and timezone come from the IP (geoSource: "ip"); ipResult only says the IP was valid, it doesn't compare locations.
Highlighted fields: action, nanpType, dipCarrierSubType, litigator, geoSource.
{
"success": true,
"credits_used": 2,
"data": {
"subscriber": "6025550114",
"optDate": "2026-10-08T21:55:43.723Z",
"action": "send",
"deliverable": "true",
"nanpType": "mobile",
"blackList": "false",
"ipResult": "valid-v4",
"dip": "success",
"dipLrn": "6025550114",
"dipPorted": "false",
"dipOcn": "6010",
"dipCarrierSubType": "WIRELESS",
"dipCarrier": "AT&T",
"dipCarrierType": "mobile",
"litigator": "false",
"litigator_type": "",
"litigator_name": "",
"geoState": "AZ",
"geoCity": "Phoenix",
"geoCountry": "US",
"geoMetro": 753,
"timezone": "America/Phoenix",
"tzOffset": 7,
"geoSource": "ip",
"error": "false",
"smsEligible": "true"
}
}Monthly cost, with the TCPA litigator scrub (+1 credit per number):
Computed from the published plans. State DNC and complainer checks never add credits. For seven-figure monthly volume, use the volume contact form.
optDate) on every lookupNot legal advice.
dncStateChecked is left out for them, so "not checked" never reads as clear.deactivationDate: data refreshed daily, with a 1 to 7 day lag, and entries expire after 45 days. It is not a reassigned-number check.On the seller side, inside the form-submit handler, before you ping any buyer, so the ping carries the validation metadata. On the buyer side, call it again when the post arrives rather than trusting the seller's metadata blindly. Both sides should count the lookup credit in their unit economics.
That's between you and your buyers. Attaching the response fields gives a buyer the same fields their own lookup would return, with a timestamp (optDate) and an audit trail if a complaint is filed.
Don't block the form submit on the result: the visitor has already converted. Make the routing decision after submit: ping buyers with the metadata and let their acceptance rules decide. Failed validation goes to your discard bucket or a lower-tier buyer that wants the volume.
No. CheckThatPhone validates the phone number itself; it does not keep a cross-customer duplicate database. Most lead-gen networks layer their own duplicate suppression on top, keyed on the phone number plus a recency window.
No. 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; without one they come from the area code. One lookup returns one or the other, so it can't compare them.
No. A number can pass every check and still be wrong to contact if the consent record is weak. The FCC's one-to-one consent rule never took effect (the 11th Circuit vacated it on January 24, 2025), but prior express written consent still applies. This page is not legal advice.
500 free lookups a month. The litigator scrub is 1 extra credit per lookup.