Ensure SMS Campaigns Reach Real Mobile Numbers
Texts sent to landlines, VoIP, and disconnected numbers fail silently and inflate your costs. 1Lookup confirms each number is a live, reachable mobile before you send, so your SMS campaigns actually land.
20%+
Of SMS spend wasted on dead numbers
99%
Live-number detection
Real-time
HLR network status
Why SMS campaigns fail
A phone number on a list is not the same as a number that can receive your message. The gap costs you money and skews every report.
Landlines and VoIP can’t receive SMS
Sending texts to landlines or unsupported VoIP numbers means guaranteed failures — that you still pay for on most gateways.
Disconnected numbers silently fail
Numbers that have been deactivated or ported away accept your spend but never deliver, skewing your campaign analytics.
Failed sends inflate cost and hurt sender reputation
High failure rates raise your effective per-message cost and can flag your sender ID with carriers, throttling future delivery.
How 1Lookup protects SMS delivery
Check each number against the live carrier network before you send, then suppress everything that can’t receive a text.
Run an HLR lookup before you send
Query the carrier’s Home Location Register to confirm the number is active and currently reachable on the network — without sending a message.
Confirm line type and carrier
Use carrier lookup to verify the number is a mobile that can receive SMS, and identify the network and porting status for routing.
Suppress and route intelligently
Skip landlines, VoIP, and dead numbers, and route deliverable messages to the correct carrier gateway for the best delivery rate.
// Confirm a number is a live, reachable mobile before SMS
const res = await fetch('https://api.1lookup.io/v1/lookup/hlr', {
method: 'POST',
headers: {
'Authorization': 'Bearer YOUR_API_KEY',
'Content-Type': 'application/json'
},
body: JSON.stringify({
phone: '+14155552671',
include_network_info: true
})
})
const { status, reachable, network } = await res.json()
// Only send to active mobile subscribers
const sendable = status === 'active' && reachableProducts that power this
Mix and match the APIs you need. Each one works on its own or together in a single request.
Frequently asked questions
How do I know if a phone number can receive SMS?
Run a carrier and HLR lookup. Carrier lookup identifies whether the number is a mobile, landline, or VoIP line, and an HLR lookup confirms the number is active and currently reachable on the carrier’s network.
What is an HLR lookup?
An HLR (Home Location Register) lookup queries the mobile carrier’s subscriber database in real time to confirm whether a number is active, reachable, roaming, or disconnected — without sending an actual message.
Will this reduce my SMS costs?
Yes. By suppressing landlines, VoIP, and dead numbers before you send, you stop paying for messages that can never deliver and you improve your delivery-rate metrics.
Can it detect ported numbers?
Yes. Carrier lookup returns the current and original carrier and porting status, so you route each message to the correct network instead of relying on outdated carrier assignments.
Do I need both HLR and carrier lookup?
They are complementary: carrier lookup tells you the line type and network, while HLR confirms live status and reachability. Together they ensure every SMS targets a real, active mobile.
Make every SMS count
Verify numbers are live, mobile, and reachable before you send — and stop paying for messages that never arrive.
No setup fees • 100 free validations • Cancel anytime