Phone intelligence, explained
Vendor-neutral guides to the concepts behind the API — what the signals mean and how to act on them. No sales pitch, just the practical version.
Fundamentals
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.
Read guideLine 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.
Read guideHLR 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.
Read guidePhone 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.
Read guideFraud & risk
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.
Read guideHow 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.
Read guidePut it into practice
Grab a free key and run these ideas against your own numbers.