Line & Carrier API
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.
What you get back
Line & Carrier is one facet of a single Qualmie response — these are the fields it contributes.
line_type- mobile · landline · voip · toll_free
carrier- Name, country, MCC/MNC
ported- Ported to a new carrier
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
Route by line type
Detect VoIP for compliance
Resolve the real carrier behind ported numbers
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 Clean a Phone List Before an SMS Campaign
Dirty phone lists quietly wreck deliverability, sender reputation, and budget. Here's a practical pre-send checklist to drop the numbers that will never convert.
Line Type Intelligence: Mobile vs. Landline vs. VoIP vs. Toll-Free
Knowing a number's line type tells you how to contact it, what it costs, and how risky it is. A plain-English guide to the four line types and what each one means for you.
HLR Lookup Explained: What It Is and When You Need One
An HLR lookup is the classic way to check whether a mobile number is active and reachable. Here's what an HLR is, what a lookup returns, and where it falls short.
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.
Phone Number Portability: What Porting Means for Your Data
Number portability lets people keep their number when they switch carriers — which quietly breaks any carrier lookup that reads a number's original range. Here's how to handle it.
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.
Risk Signals
Is this number risky?
Score fraud and abuse risk from disposable, VoIP, and recently-disconnected signals — before a bad number costs you.