Spam labels and number reputation

Who this is for: anyone whose answer rate has dropped without a routing change, or who is about to reuse a number with unknown history. Symptom this explains: the number works, the call connects, and nobody picks up.

Some of this page is not yet documented

The mechanics below are how carrier labelling works across the US industry and apply to any number, on any platform. What Moja specifically exposes, checks, or does on your behalf is not documented today and is flagged inline. Treat the flagged items as open questions for your account team, not as product behaviour.

What a spam label actually is

There is no single list. Three separate systems produce the effect people call “spam likely”:

Analytics engines. Carriers license call-scoring services that score numbers on calling patterns — volume, call duration, answer rate, complaint reports, and how long the number has been in service. A low score renders on the handset as Spam Likely, Scam Likely, Potential Fraud, or similar. Each carrier uses a different engine, so a number can be labelled on one network and clean on another.

STIR/SHAKEN attestation. Originating carriers sign outbound calls with an attestation level indicating how well they know the caller has the right to use that number:

Attestation	Meaning
A — Full	The carrier knows the customer and knows they have the right to use that number
B — Partial	The carrier knows the customer but cannot verify their right to that specific number
C — Gateway	The carrier has passed the call along without verifying either

Low attestation does not itself label a call, but it removes the protection that keeps a good number from being scored badly.

Handset and app blocking. Consumer call-blocking apps and OS-level filters apply their own lists, independent of the carrier.

This matters for pay-per-call in one specific way: labelling attaches to the caller ID being displayed, so it is primarily an outbound and callback problem. A tracking number that only receives calls is not scored by these systems for its inbound traffic.

What causes a number to get labelled

• High call volume from a new number with no history
• A high proportion of very short calls — the pattern of a dialler, and of a number people hang up on
• A low answer rate sustained over time
• Consumer complaints or in-app spam reports
• Calling numbers on a DNC list
• Reusing a number that was previously used for a high-volume outbound campaign — reputation follows the number, not the owner

Note

This is the practical reason to care about a number’s history when you port one in or buy recycled inventory. A number that arrives already labelled will underperform from day one, and nothing in your routing configuration will explain it.

What to do about it

1. Confirm it is actually a labelling problem. Rule out routing first — a call that connects, has real duration on the Moja side, and still gets no engagement is a different problem from a call that is never answered at all. Compare answer rate across several of your numbers over the same period; a per-number collapse points at labelling, an account-wide one does not.

2. Check the number against the free carrier lookups. The major US carriers each publish a portal where you can check a number’s reputation and file a remediation request. They are separate systems and you have to check each one. There are also aggregated commercial services that submit to several at once.

3. Register the number. Branded-caller and number-registration programmes let a business associate a number with a verified identity, which materially reduces mislabelling. Registration is done with the analytics providers and carriers, generally through your voice provider.

4. Fix the behaviour that caused it. Remediation on an unchanged calling pattern is temporary. Reduce short-call volume, spread volume across more numbers, honour opt-outs promptly, and stop calling numbers that never answer.

5. Retire numbers that stay labelled. Some numbers do not recover in a useful timeframe. Replacing the number is often cheaper than continuing to appeal it.

[CONFIRM — product]

Confirm with product and engineering, and then replace this section with the specifics:

• Does Moja surface any reputation or spam-label signal on a number, in the Numbers list or in reporting?
• What STIR/SHAKEN attestation level do calls originated through Moja carry, and does it vary by number type or by whether the number was purchased or ported?
• Does Moja submit numbers to any branded-caller or number-registration programme on the customer’s behalf, or is that the customer’s job with their own provider?
• Is there a supported path to request remediation for a Moja-provisioned number, and who runs it?
• Is a number’s prior usage history visible before purchase, or available on request?

What Moja does give you today

These are documented and available now, and they cover the inbound side of the same problem:

• Blocking — stop specific numbers or country codes at the scope that fits. See Block unwanted callers.
• TCPA scrubbing — campaign-level compliance scrubbing, via the default provider or a third party. See TCPA compliance: default and Blacklist Alliance.
• Duplicate handling — stop paying repeatedly for the same caller. See Configuring sticky caller and duplicate call routing.
• QAI spam dispositions — classify calls as spam or scam from the transcript, so the pattern shows up in reporting rather than in your margin. See QAI quick start.

Troubleshooting

Symptom	Likely cause	Fix
Answer rate fell on one number, others unchanged	That number is labelled on at least one carrier	Check the carrier lookup portals for that number
Answer rate fell across every number at once	Not labelling — look at the traffic source or the offer	Compare publisher-level performance in reporting
A newly ported number performs badly from day one	Inherited reputation from its previous owner	Check its reputation before assuming a configuration fault
Calls connect with real duration but never convert	Call quality, not labelling	QAI quick start
Remediation worked, then the label came back	The calling pattern that caused it did not change	Reduce short-call volume and spread across more numbers

Related

• Numbers overview
• Port a number to Moja
• Block unwanted callers
• TCPA compliance: default and Blacklist Alliance