Risk Signals API
Is this number risky?
Score fraud and abuse risk from disposable, VoIP, and recently-disconnected signals — before a bad number costs you.
What you get back
Risk Signals is one facet of a single Qualmie response — these are the fields it contributes.
risk.level- low · medium · high
risk.score- 0–100 risk score
risk.voip / disposable- Fraud-relevant flags
curl https://qualmie.dev/v1/liveliness \
-H "Authorization: Bearer sk_live_1a2b3c..." \
-H "Content-Type: application/json" \
-d '{ "phone_number": "+12125550100" }'{
"phone_number": "+12125550100",
"valid": true,
"live": true,
"reachable": true,
"line_type": "mobile",
"carrier": {
"name": "Verizon Wireless",
"type": "mobile",
"country": "US",
"mcc": "310",
"mnc": "004"
},
"ported": false,
"risk": {
"level": "low",
"score": 8,
"voip": false,
"disposable": false,
"recently_ported": false,
"recently_disconnected": false
},
"checked_at": "2026-07-17T17:04:11Z",
"latency_ms": 187
}Common use cases
Block disposable numbers at signup
Flag OTP-abuse risk
Prioritize manual review
Learn more
How to Detect VoIP and Disposable Phone Numbers
VoIP and disposable numbers drive most phone-based fraud. Learn the signals that flag them and how to screen them out of your signup flow without adding friction for real users.
How to Reduce OTP and SMS Verification Fraud
OTP flows are a favorite target for account farming and SMS pumping. Screening numbers before you send the code cuts both — here's how to design it without friction for real users.
Explore the suite
All products →Liveliness
Is this number active right now?
Confirm a number is well-formed, assigned, and live on a carrier network at request time — not just correctly formatted.
Reachability
Can it receive a call or SMS today?
Know whether a live number can actually take a call or text before you spend on delivery or dialing.
Line & Carrier
Who carries it, and what kind of line?
Resolve the current carrier, country, and line type — mobile, landline, VoIP or toll-free — including ported numbers.