Phone Number Validation is one of the 
iClosed Data Intelligence features that verifies whether a lead’s phone number is real, reachable, and usable as soon as it is entered on the form.
It helps you block fake or uncontactable leads before they progress through your funnel and will look up key identifiers such as number validity, country, line type (mobile or landline), carrier, and prepaid status - before they book a call.
Important note
Phone number validation can be turned on by the account owner only.
Each lookup consumes 1.5 credits
How Does It Work
The validation runs a comprehensive phone lookup and provides the following feedback on entry:
Phone number validity and format
Phone line type (Mobile, Landline, VOIP)
Carrier information and prepaid/postpaid status
Activity score and reachability
Logic
Phone Validation confirms if a lead’s number is real and usable, with country / line / carrier / prepaid info. If invalid or limited, we skip Credit Score to save credits.
See details here
See details here
Here is the validation logic:
We will first check whether the phone number is valid/existing or not
This validation is default and mandatory for both validation modes.
Then, we will check line type: Mobile or Landline or VOIP.
If it's a Mobile phone number, we will check whether it's prepaid or postpaid
Prepaid Prepaid is considered a lower-intent or higher-risk lead, but it does not mean the phone number is invalid.
Postpaid is considered as higher-intent lead, as by having a long-term carrier contract means higher trust and stability
Landline/VOIP phone numbers are flagged as higher-risk leads.
In short, Phone Validation prevents a lead from passing through the form until a valid phone number is provided:
Phone format is valid
Mobile
Postpaid
The rate limit is set to 5 attempts per IP.
After 5 failed attempts, iClosed will block further validation, mark lead as potential (unqualified) and skip any email or/and Credit Score check after.
Lookup Terms
Every new number entered / edited will be considered as a new lookup.
Validation for Phone numbers which are in your
Global Data and were validated already won't be validated again - won't count against your credit usage. Phone number validation can be used for
lead qualification (Disqualification or Conditional Routing) and
as a precondition for Credit Score check
After a lead with the same IP attempts to pass through phone validation 5 (five) times, phone validation will stop to prevent additional costs, including the credit score check, and will consider the lead as potential.
Results
Reduces time spent on calling disconnected or invalid phone numbers.
By identifying line types, you can optimize your outreach strategy (e.g. prioritize mobile numbers for SMS or direct calls).
Improve lead quality by filtering out leads with VOIP numbers, prepaid phones, or numbers with low activity scores.
Better spam prevention as humans who are trying to re-enter fake phone numbers will be stopped immediately
Pro tips
As the phone number validation is one of the pre-conditions for Credit Score check, iClosed will skip the Credit Score check if the phone number was returned as invalid or limited (Landline, VOIP, Mobile Prepaid) to prevent spending of the wallet credits.
Setting Up Phone Validation
Here's how you can set up Phone Validation for your account:
Turning Phone Validation ON
Navigate to 
AI Scheduler - Events page to turn on Phone Validation:
Click on the Event where you want to apply Phone Validation
Select Data Intelligence section
Click on the toggle button to turn it on
Save configuration and test it out
Make sure to purchase credits in 
Settings - Billing before testing it if you haven't already. Here's a quick video on how to turn it on:
Pro tips
Once you've purchased the credits, kindly note that it's advisable to turn on auto-recharge in your wallet to ensure you always have enough credits which will prevent Data Intelligence features from stopping.
Finding Validation Results
Validation results can be found in 
Global Data - all sections or inside of the lead Contact Card:
Global Data
Global Data - all sections → make sure the column Phone validation is selected
Contact Card
Journey, along with all phone number edits
FAQs
Where can I see credits usage for my Phone number validations?
Where can I see credits usage for my Phone number validations?
You can view Phone Validation credit usage from:
iClosed will store logs showing each validation attempt, including the validated email, result (valid or invalid), credits consumed, and the exact time the validation was triggered.
Is Phone Validation mandatory for Credit Score check
Is Phone Validation mandatory for Credit Score check
yes, it is, and Credit Score check can't be turned on without phone and email validation both.
What happens if I don't have enough credits in wallet?
What happens if I don't have enough credits in wallet?
In case you run out of wallet credits, phone validation as any other Data Intelligence feature will be stopped.
To prevent that from happening, we advise turning on auto-recharge in your wallet in 
Settings - Billing - Credits Usage.
Can I re-validate phones that were collected by iClosed before validation was turned on?
Can I re-validate phones that were collected by iClosed before validation was turned on?
No, that isn't available.
What you can do as a workaround is to copy phone number of a lead and try to enter it again on the form where Phone Validation is turned on.
In case you decided to do this, it's advisable to use event specifically made for your appointment setters to use, or for this purpose only, to avoid messing up the data in your main events embedded in your funnel.
But, take into consideration that you may hit IP rate limit in case you try to validate phone numbers more than five times.
From the validation perspective, is it better to have email as primary contact information or phone number?
From the validation perspective, is it better to have email as primary contact information or phone number?
To be fully transparent, there is no right or wrong answer here. The best answer is behind the question on which of these two your leads are more likely to respond back.
If it's a phone number, rather than email, you should collect phone first and while doing so, to validate every number entered.
Is validation available to all international phone numbers?
Is validation available to all international phone numbers?
Yes, iClosed phone validation service is applicable to all international phone numbers, as long as they pass through default format validation.
Is Phone Number Validation used for outreach or compliance?
Is Phone Number Validation used for outreach or compliance?
Phone Number validation primary function is to help you identify your lead and outreach opportunities easier.
It helps you unveil what you can expect from the phone number entered and not just that, but to ensure only leads with contactable phone numbers can book a call with your team.
Learn more