State do-not-call scrub for outbound calling and SMS

The federal Do-Not-Call registry gets all the attention, but it is not the only list that can cost you. Most US states run their own do-not-call registries, several with penalties that are enforced separately from — and on top of — federal exposure. And beyond the registries sits a quieter risk: numbers whose owners have a documented history of filing DNC and TCPA complaints, who are disproportionately likely to file the next one against you.

Most teams scrub state registries late, rarely, or never, because it traditionally means buying and merging per-state files on your own schedule. The dncOther add-on folds both checks into the lookup you are already making — and it's free.

The fix: one boolean, zero extra credits

Enable dncOther: true on any request to POST /v1/lookup (or the matching option on a bulk CSV job). We screen the number against state do-not-call registry data covering 40 states, refreshed weekly, and against our national complainer list of roughly 700,000 numbers with documented DNC/TCPA complaint history. Four fields come back alongside the normal carrier data. credits_used does not change.

What you get back

See the State DNC & Complainers field group in the docs for the full reference.

The honest part: coverage

We hold registry data for 40 states. Eleven states — Florida, Colorado, Indiana, Massachusetts, Missouri, Pennsylvania, Texas, Wyoming, Louisiana, Oklahoma, and Tennessee — only distribute their lists to organizations that register with the state directly, so they are not in our data. A blank result for a Dallas number does not mean the number is clear; it means Texas wasn't checked.

Most data vendors let that ambiguity ride. We don't: dncStateCovered is computed on every scrubbed lookup from the number's area code (deliberately not from IP-based geolocation), so your suppression logic can branch on it explicitly — suppress on a match, trust a clear result in covered states, and fall back to your own per-state scrub file for the eleven others.

A complete request

curl --request POST \
  --url 'https://api.checkthatphone.com/v1/lookup' \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
    "phone": "8182925409",
    "dncOther": true
  }'

A state-registry match looks like this:

{
  "success": true,
  "credits_used": 1,
  "data": {
    "subscriber": "8182925409",
    "optDate": "2026-08-13T17:01:48.188Z",
    "action": "send",
    "deliverable": "true",
    "nanpType": "mobile",
    "blackList": "false",
    "dip": "success",
    "dipLrn": "8182925409",
    "dipPorted": "false",
    "dipOcn": "6010",
    "dipCarrierSubType": "WIRELESS",
    "dipCarrier": "AT&T",
    "dipCarrierType": "mobile",
    "dncOtherChecked": "true",
    "dncStateResult": "STATE DNC",
    "dncComplainerResult": "",
    "dncStateCovered": "true",
    "geoState": "CA",
    "geoCity": "agoura hills",
    "geoCountry": "US",
    "timezone": "America/Los_Angeles",
    "tzOffset": 8,
    "geoSource": "area-code",
    "error": "false",
    "smsEligible": "true"
  }
}

Notice two things: credits_used: 1 — the scrub added nothing to the bill — and action is still send. A DNC match is informational by design: whether a registered number is contactable depends on consent you may already hold (an existing business relationship, prior express written consent), so the routing decision stays yours.

How to wire it up

1. Turn it on everywhere (recommended)

It's free, so the simplest posture is dncOther: true on every lookup you already make. Suppress on dncStateResult or dncComplainerResult matches unless you hold documented consent, and log dncStateCovered with the result for your audit trail.

2. Bulk scrub before a campaign

Tick the State DNC & complainers scrub option on a bulk CSV upload and the result file carries the four columns for every row. Registry data refreshes weekly, so re-scrub long-running lists on at least that cadence.

3. Layer it with the litigator scrub

The litigator filter catches professional plaintiffs; the DNC scrub catches registered consumers and complaint-history numbers. They overlap less than you'd hope, which is exactly why running both is the standard posture for outbound compliance.

Inline FAQ

What this isn't

This is not federal DNC compliance — we do not check the national registry, and you must honor it through your own scrub process. It is also not a consent record: a number absent from every list can still be wrong to contact without underlying consent, and a number on a state registry can be fine to contact with it. Treat the scrub as a defensive data layer feeding your compliance logic, not as the logic itself.

Pricing for this use case

Free, on every plan, including the free tier and bulk CSV jobs. A scrubbed lookup costs exactly what the lookup costs — 1 credit — and the flag adds nothing on top. There is no catch to look for: the data layers this scrub reads are ones we already maintain, so we'd rather every campaign that runs through us be scrubbed than meter it.