4 articles.
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
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
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
