Liveliness API
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.
What you get back
Liveliness is one facet of a single Qualmie response — these are the fields it contributes.
valid- Well-formed and assigned
live- Active on a carrier network now
checked_at- Timestamp of the live check
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
Clean lists before a send
Reject dead numbers at signup
Re-validate aging contact data
Learn more
What Is Phone Number Liveliness?
Liveliness tells you whether a phone number is active, reachable, and safe to use right now — not just correctly formatted. Here's what it measures and why it matters.
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 →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.
Risk Signals
Is this number risky?
Score fraud and abuse risk from disposable, VoIP, and recently-disconnected signals — before a bad number costs you.