Does validation send SMS or calls?

No. It is a technical status check on the numbering: the recipient receives nothing and is not disturbed.

Does it work on landlines?

The service targets mobile numbering. Landline or non-mobile numbers come back as invalid or undetermined depending on the response received.

4 credits per number, with a minimum batch of 500 numbers. The estimated cost always appears before you confirm, and credits are universal across services.

How often should I revalidate a list?

It depends on your collection rate and market. A good rule is to validate new contacts on entry and re-check active segments every three to six months.

Does a valid result guarantee the person will answer?

No. It reports the technical status of the line at the time of the check, not the person's availability or their consent to commercial contact.

Phone number validation and HLR lookup: a practical guide

Key points

One outcome per row: valid, invalid or undetermined, with the number normalised to international format.
Cost: 4 credits per number, minimum batch of 500 numbers, estimate shown before you confirm.
Removes non-existent numbers, malformed rows and duplicates before any send.
It is technical line status: it does not certify identity, an answer, or consent to be contacted.

What an HLR lookup is

The HLR (Home Location Register) is the registry where mobile operators keep the status of their numbering. A lookup queries that infrastructure to learn whether a number is assigned and usable, without sending anything to the user.

Commercially this is usually called number validation: the practical output is a short outcome for each row, telling you whether that contact is still worth keeping.

Why lists decay over time

Mobile numbers change owner, get disconnected or reassigned. A database collected over years inevitably holds dead rows, plus typos, missing country codes and duplicates created by repeated imports.

Every useless row has a cost: paid sends that never land, worse delivery rates, distorted reporting and sender reputation damage. Validation brings the database back to its real size.

How the check works

Upload a CSV or XLSX, or paste the numbers. The platform normalises everything to E.164, discards unreadable rows, removes duplicates, then shows the real number of checks and the credit cost before you confirm.

The job runs in the background and we email you when it is done. The output CSV contains the normalised number and the outcome, ready to import back into your CRM or match on the check ID.

How to read the outcomes

Valid means an existing, usable mobile line. Invalid means the number does not exist, is unassigned or is unusable. Undetermined means the operator returned nothing reliable: the row stays in the file, clearly flagged.

Read the results statistically: on large lists the share of invalid rows tells you how degraded the database was and how much you save by not messaging them.

Validation and channel checks: the right order

Validation says whether the line exists; channel checks such as WhatsApp, Viber, RCS, iMessage and Telegram say where the contact is reachable. They answer different questions and work well together.

The recommended order is to validate the whole list first, then pass only the valid numbers to channel checks. You spend fewer credits overall and get cleaner segments.

Operational best practice

Validate at collection time (forms, imports, lead campaigns) and then periodically on the legacy database: many teams re-run the check every three to six months on active segments.

Store the check ID alongside the outcome: it lets you prove when a row was verified and rebuild your cleaning history without paying twice.

Frequently asked questions

Does validation send SMS or calls?: No. It is a technical status check on the numbering: the recipient receives nothing and is not disturbed.
Does it work on landlines?: The service targets mobile numbering. Landline or non-mobile numbers come back as invalid or undetermined depending on the response received.
What does it cost?: 4 credits per number, with a minimum batch of 500 numbers. The estimated cost always appears before you confirm, and credits are universal across services.
How often should I revalidate a list?: It depends on your collection rate and market. A good rule is to validate new contacts on entry and re-check active segments every three to six months.
Does a valid result guarantee the person will answer?: No. It reports the technical status of the line at the time of the check, not the person's availability or their consent to commercial contact.

Validate your list before the next campaign

Upload the database, drop the dead rows and restart with real numbers. You pay only for checks performed, from a single credit wallet.

Start a validation Open the service page

Related service: Open the service page for credit costs, accepted file formats and the outcomes you get back. Open the service page

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Phone number validation and HLR lookup: how to clean a database