Spam Check Add-on, available in Caller Identification API, flags phone numbers likely tied to unwanted or high-risk calling activity, returning a simple is_spam = true/false signal. An AI-powered model reads phone metadata, caller reputation, calling patterns, and feedback data provided to assess spam, robocall, and fraud risk, then consolidates that read into a single response you can act on.
What is a Spam Check? #
The Spam Check Add-on is an AI-powered caller-reputation signal for Caller Identification API. It returns a single is_spam value of true or false that tells you whether a phone number is likely associated with unwanted or high-risk calling activity.
The signal helps you separate callers who may need extra scrutiny from those who do not. It accounts for risks tied to spam calls, robocalls, scam activity, and potential fraud before you decide how to display, route, verify, or handle an interaction.
What types of calls can Spam Checks identify? #
The Spam Check Add-on accounts for four related forms of caller-reputation risk:
- Spam calls: Unwanted or nuisance calling.
- Robocalls: Automated or prerecorded calling activity.
- Potential fraud calls: Patterns tied to scams, impersonation, or deceptive calling.
- High-risk caller reputation: Numbers whose available signals point to a higher likelihood of abusive or unwanted calling.
All four roll up into the single is_spam output.
How does the AI-powered signal work? #
The model evaluates phone metadata, caller reputation, calling patterns, provided feedback data, and other available risk signals to assess whether a number is likely associated with spam, robocall, fraud, or other high-risk behavior. It consolidates that assessment into one response, so you can make a consistent decision without managing separate categories or stitching together multiple data sources.
Which products have Spam Checks available? #
Spam Checks are available as an add-on to Caller Identification API. When enabled, the response includes the is_spam attribute, returned as true or false.
The signal is additive. It does not replace your existing Caller Identification API response attributes, and it will not change any result it returns. You control how to act on the signal.
How should you use the is_spam signal? #
Spam Checks are a decisioning signal, not an automatic action. A true result points to potential risk, and the final call to answer, route, display, suppress, or block stays with you. Common ways to put it to work:
- Label a caller as potential spam
- Route a call through extra verification or an IVR step
- Limit or block traffic based on your own policy
- Prioritize an interaction for review
What are the common use cases? #
| Use case | How it works | Why it matters |
| Inbound Call Screening | Score inbound callers in real time. Route is_spam=true to extra verification or an IVR step, and send less risky callers straight to an agent. | Protects agent capacity and reduces exposure to nuisance and scam calls. |
| Fraud and Risk | Flag high-risk inbound numbers for review before sensitive actions such as account changes. | Adds a caller reputation signal alongside your existing risk checks. |
| Outbound Number Reputation Monitoring | Query your own outbound phone numbers to find out whether any have been flagged. | Flagged numbers get blocked or labeled as spam, which lowers answer rates. Early visibility lets you act before outbound performance drops. |
How often should this check be performed? #
For real-time caller workflows, check every time you query Caller Identification API. Caller reputation shifts as numbers are reassigned and calling behavior changes.
Does the Spam Check Add-on have additional costs? #
Yes. Spam Check Add-on is priced at $0.005 per query, with volume pricing available. Contact us for volume pricing and enablement details.
Why aren’t Spam Checks part of Caller Identification API by default? #
Caller Identification API supports plenty of workflows that only need caller name, brand, or identity context. Spam risk is not required for every lookup, and it runs through separate AI-powered risk processing. The add-on is enabled on a per-customer basis for the customers who need the signal.
What is the typical hit rate? #
Hit rate varies by list source, traffic channel, number type, geography, and use case. Rather than applying one expected rate to every customer, we recommend setting a customer-specific baseline once the add-on is enabled. Across our customers, we see roughly .3-2% of numbers flagged as spam.
How accurate are Spam Checks? #
An is_spam=true result is reserved for the numbers we have the highest confidence are tied to risk or spam activity. Our accuracy on those flagged numbers is over 90%.
Are Spam Checks available for trial and self-serve users? #
Yes. Spam Checks are available across all subscription types, including trial and self-serve accounts.
Do Spam Checks replace litigator or other compliance checks? #
No. Spam Checks are a caller-reputation and risk signal. It is not a DNC check or a litigator check, and it is not a guarantee that a caller is or is not legitimate. Keep applying your own compliance and call-handling policies, and pair Spam Checks with the right tool for each job.
For related compliance signals, see Does Trestle Offer DNC Checks? and our Litigator Check Add-on.
Want to see how many of your inbound callers get flagged as spam? Talk to our team about enabling Spam Checks on your account, and bring a caller-reputation signal into your inbound call routing and verification workflow.