Phone Number Validator

Voiso’s Number Validator is a powerful tool that helps you ensure the accuracy and quality of your contact lists. It validates phone numbers in bulk, checking for formatting errors, confirming allocation to service providers, and providing valuable insights like country, carrier, and reachability status.

Simply upload your list of phone numbers in a CSV file, choose your desired level of validation (Number Profile or Line Activity), and submit your request. Our system will quickly process your list, automatically checking for errors and providing a detailed report on each number.

• Boost campaign success: Eliminate wasted calls and connect with real people, leading to higher conversions and more efficient campaigns
• Unlock valuable contact insights: Gain a deeper understanding of your audience with detailed information about each number, including location, carrier, and reachability status
• Clean lists, clear savings: Reduce dialing costs and optimize your budget by removing invalid and unreachable numbers
• Improved compliance & data protection: Mitigate risks by ensuring your contact lists are accurate and up-to-date, helping you stay compliant with data protection regulations.
• Tailored validation options: Choose between Number Profile and Line Activity to get the level of detail you need
• Easy to use: Validate large lists in bulk with a user-friendly interface and actionable CSV reports

Phone validation ensures compliance by identifying and removing invalid, inaccurate, or opted-out numbers from your contact lists. This reduces the risk of contacting individuals who have not provided consent, helping you adhere to regulations like TCPA, GDPR, and other data protection laws. By maintaining clean and verified data, you avoid penalties, enhance customer trust, and meet legal requirements for responsible outreach.

Phone validation ensures that only accurate and active contact data flows across all channels—voice, SMS, chat, and social platforms. This improves message deliverability, reduces failed interactions, and enhances customer experience by enabling seamless communication. Clean, validated data also supports personalized outreach and ensures compliance across all channels, driving better performance in omnichannel campaigns.

Validators improve ROI by eliminating invalid and unreachable numbers, ensuring agents focus only on real, active contacts. This reduces wasted call attempts, minimizes operational costs, and increases connection rates. Additionally, insights like carrier and number type allow for targeted outreach, optimizing campaign performance and driving higher conversions, resulting in a more efficient use of resources and improved returns.

1. Validation Rate: Percentage of valid numbers in the contact list.
2. Invalid Number Rate: Percentage of numbers flagged as incorrect or unreachable.
3. Connection Rate: Number of successful calls or message deliveries to validated contacts.
4. Cost Savings: Reduction in expenses from avoiding invalid numbers.
5. Agent Talk Time: Increase in productive time spent connecting with valid contacts.
6. Campaign Conversion Rate: Percentage of validated contacts that lead to successful outcomes (e.g., sales or appointments).
7. Return on Investment (ROI): Improved campaign efficiency and results compared to total validation costs.

1. Accuracy: Ensure the validator can reliably identify active, valid numbers with minimal false positives.
2. Data Insights: Look for tools that provide detailed information like carrier, country, number type, and reachability.
3. Scalability: Choose a solution that can handle bulk validation for large contact lists efficiently.
4. Compliance: Verify the tool helps meet regulations like TCPA and GDPR by identifying opted-out or invalid contacts.
5. Integration: Ensure it integrates seamlessly with your CRM, dialers, and other systems.
6. Ease of Use: Opt for a platform with an intuitive interface for quick setup and smooth workflows.
7. Cost-effectiveness: Evaluate pricing based on validation volume and ROI improvements.

Below are the main methods and best practices you can use:

Format and Syntax Validation

1. E.164 Formatting:
   – Convert the phone number to E.164 format (e.g., +14155552671).
   – This ensures consistency and makes it easier to apply further checks or integrations with third-party services.
2. Library-Based Parsing:
   – Use libraries such as libphonenumber (Google) or equivalent packages in your programming language to parse the phone number, validate its syntax, and format it properly.
3. Country and Area Code Checks:
   – Validate that the country code and area code are recognized and not obviously incorrect (e.g., “999”).

Note: Syntax validation alone can’t confirm if the number is active, nor can it definitively determine line type (cell vs. landline vs. VoIP). It only ensures the number is in a valid format for its region.

Carrier and Type Lookups (Phone Intelligence APIs)

Many online platforms and telecom providers offer APIs to look up a phone number’s carrier, line type, and general status. Common options include:

• Carrier Data Services
  – Some regions allow direct queries into databases maintained by telecom providers or government regulators. In the U.S., you can utilize the Local Number Portability (LNP) database for official porting and carrier info.
• Enterprise Solutions
  – Services like Whitepages Pro and Ekata (formerly Whitepages Pro) offer “phone intelligence” solutions that include line type detection, activity (e.g., recently active), and reputation scoring (spam or fraudulent number flags).

Pros:

• High accuracy for many countries.
• Real-time or near real-time data from telecom sources.
• Helpful when compliance, fraud prevention, or advanced segmentation is needed.

Cons:

• These APIs are typically paid services.
  Global coverage and accuracy can vary by region.
  HLR (Home Location Register) Lookups (for Mobile Lines)
• For mobile numbers in certain countries, a Home Location Register (HLR) lookup can confirm whether a phone is active on a mobile network.
• HLR Check: Determines which mobile network currently hosts the SIM. If the query indicates an active mobile subscriber, you’ll know it’s a working cell phone.
• Limitations: Not all providers or countries offer publicly accessible HLR lookups. Moreover, HLR checks do not cover landline or VoIP.

Call and SMS Testing

If a formal lookup service is unavailable or cost-prohibitive:

Outbound Test Call
– Programmatically place a call to the number and monitor call progress events.
– If the call is answered and no immediate call-failure signal occurs, you have a strong indication it’s valid and active.
– Some systems can return signaling codes that differentiate mobile vs. landline, though VoIP lines often mimic one or the other.

SMS Verification
– For numbers that accept SMS, sending a verification code (or using A2P SMS services) can confirm if it’s truly a mobile/VoIP SMS-capable line.
– Traditional landlines typically can’t receive SMS (though some third-party “landline texting” services exist).

Note: Test calls and SMS may not always distinguish between mobile and VoIP. Many VoIP lines can receive calls or texts just like a mobile number.

CNAM (Caller ID Name) Queries

– Some services provide a caller ID name (CNAM) lookup.
While CNAM alone won’t definitively determine line type, it can offer additional context (e.g., if it returns a business name typical of VoIP-based lines).

Fraud Scoring and Reputation Checks

Services such as Pipl, Telesign, or IPQS can run phone numbers through fraud or reputation databases.

If a number appears on spam or robo-calling lists, that might indicate it’s a disposable VoIP or a heavily rotated marketing number.

Manual Verification and Cross-Referencing

For smaller scale scenarios, you can cross-reference public directories (like Whitepages in the U.S.) to see if a number is listed as a residential landline or a mobile number.

Cross-referencing social media or professional networks can also confirm if a phone number is genuinely used by a person or business.