14 articles.
Research
WhatsApp authentication rates for 44 markets (Meta, October 2026), why SMS OTP prices differ by country, and when a number check costs less than a wasted code.
14 min read
Fraud prevention
For number providers, MVNOs and virtual-number resellers: quarantine rules by country, the FCC database, and HLR and app-account checks before reissue.
12 min read
Fraud prevention
No public list ranks SMS pumping countries. How to sort destinations into allow, gate and block from published sources and your data, and which ranges to block.
12 min read
Guides
MCC and MNC codes identify every mobile network. How the ITU E.212 system works, how to read a code like 310260, MCC vs calling code, and a list by country.
13 min read
Deliverability
HLR lookup prices per number and per 1,000: what drives the cost, the pricing models on the market, hidden fees, and how to estimate a list before you pay.
7 min read
Guides
Free carrier lookup methods (prefix data, regulator tables, web tools), why they fail for ported numbers, and when a paid live lookup is worth it.
10 min read
Developers
No. libphonenumber checks numbering-plan metadata, not the network. What isValidNumber proves, what it can't, and how to check if a number is live.
7 min read
Guides
MCC/MNC lookup by phone number: why the prefix shows only the original network, how to get the current code with MNP or HLR, and 5 mistakes to avoid.
8 min read
Guides
What the IMSI, MSISDN, ICCID and IMEI are, where each lives, what changes when you port or swap a SIM, and why the IMSI must never leave the network.
8 min read
Deliverability
What an SMS delivery report is, what DELIVRD, UNDELIV, EXPIRED and REJECTD mean, why 'delivered' isn't proof of reading, and why DLRs go missing or wrong.
7 min read
Guides
Absent subscriber: the number exists but the phone is off or out of reach. Unknown subscriber: the number is not assigned. Each HLR result and what to do next.
10 min read
Guides
To check if a phone number is active, validate it, then run a carrier or HLR lookup for live status; app checks show registration. Free methods and limits.
8 min read
Guides
Validation checks the digits, MNP finds the current network, HLR asks the network if the number is live. What each answers, costs and misses.
7 min read
Deliverability
A delivery receipt reports what happened after you sent an SMS. An HLR lookup asks the network before you send. What each can see, miss and cost.
7 min read
