What is a Phone Number Verification API?
Phone verification APIs are, as their name suggests, used to verify phone numbers. Verification APIs and services review phone numbers and make sure they’re valid (i.e., they exist) and still in use. They can also be used to standardize phone numbers and identify geographic information for compliance purposes.

Many APIs are web-based, which means they are not downloadable. Instead, they must be integrated into your website, database, or other application via programming. While this may initially sound daunting, Quick Start Guides are available to make this process as simple as possible. Web-based, programmable APIs are also preferably since organizations can customize them to fit their unique communication and marketing needs.
Benefits of Using Phone Verification APIs
Verifying phone numbers is the primary benefit to using phone validation APIs. However, there are also many other benefits that come from using such a service, including:
- Ensures Compliance – Another feature of verification APIs is that they define time zones to restrict calling and contact times, ensuring your organization stays in compliance with state and federal regulations.
- Returns Number Information – APIs return many different types of phone number information, some of which we’ll cover more in-depth later; this information allows you to better customize and target your campaigns.
- Saves Time and Money – Using a validation API saves you time and money by removing invalid and unused numbers from your contact lists before you try to send out texts mass SMS service or call those numbers.
- Provides Accurate Data – Invalid and unused numbers can skew the data from your campaigns, limiting your ability to accurately gauge campaign effectiveness and identify areas for improvement.
These are just a few of the benefits that come from using phone verification APIs. They clearly demonstrate why verification APIs are so widely used and how they quickly pay for their investment. Using an accurate and reliable service does more than just validate phone numbers; it can revolutionize your entire communication and marketing strategy.
How To Verify a Number
The first step to verify a phone number is to integrate your chosen verification API. Research different companies carefully in order to make sure their API will be able to meet your needs. Scalability and price are two of the most important factors. Will the API be able to handle future as well as current verification needs, and will it remain cost-effective?
Once you’ve chosen and integrated a reliable phone verification API, upload your phone numbers via contact lists. The API will run through these lists and verify numbers are valid and active.
The API will return information on which numbers will and won’t work, allowing you to remove invalid and inactive numbers from your contact lists. This boosts deliverability for your campaigns, allows you to better target and service customers, and ensures sensitive information always goes to the right person.
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LRNs and Why They’re Important for Verification
Besides validating them, the API will also look at the digits of each telephone number and return carrier information and the Location Routing Number (LRN). The LRN is a unique 10-digit identifier that allows phone numbers to be found and dialed. So when you input a number to call, the local telephone exchange will search for that number’s LRN to call it.
LRNs are important for three reasons, all of which relate to phone number portability: service provider portability, service portability, and geographic portability. What this essentially boils down to is that if you switch telephone service providers or move to a different area, you’re still able to keep your current phone number. Only the LRN will need to be updated.
However, select carrier information and the LRN will only be returned for phone numbers administered by the North American Numbering Plan Administration (NANPA). This means that only phone numbers in the U.S. and Canada can be fully verified.
Information Provided by Verification APIs
Besides providing verification and standardization, phone verification APIs also gather data about phone numbers and their users. This information may be essential for compliance and security purposes. It may also just be helpful, such as when it’s used for marketing purposes. APIs can return information such as:
- Validity – Whether the phone number is valid (valid [“true”] or invalid [“false”])
- Use – What the phone number is used for (commercial, individual, etc.)
- Company – What company the phone number is registered to (Verizon, Sprint, etc.)
- Country – The country the phone number belongs to (US, Canada, etc.)
- State – What state the phone number belongs to (VA, NC, CA, etc.)
- Rate Center – The geographic location the phone number belongs to (Norfolk, Suffolk, etc.)
- County – The county the phone number is from (Middlesex, etc.)
- ZIP Code – The ZIP code the phone number belongs to (23320, 86753, etc.)
- Time Zone – The time zone the phone number belongs to (EST, MCT, etc.)
- Assignation – The date the phone number was assigned to its current owner (9/10/2001, etc.)
- Wireless – Whether or not the phone number is wireless (mobile vs. landline)
All of the above data and more can be returned depending on the needs of the organization. We listed a lot of information related to location, but there’s even more data available. For example, you can also return the longitude and latitude of the number’s telecom address.
Making Phone Verification Easy
Phone and mobile number verification APIs are beneficial for a number of reasons. They can help organizations better service customers, ensure sensitive information reaches the right party, increase profits by mitigating fruitless outreach efforts, and more. Considering all of these benefits, it’s understandable why so many companies are integrating a verification API into their communication and marketing strategies.
Esendex’s phone validator has been the go-to, cost-effective solution for phone number validation since 1999. Our API validates, standardizes, restricts, and provides information on all of the phone numbers you upload almost instantaneously. Our API fits every budget and is completely scalable to fit every need.
Sign up today to start validating phone numbers and boosting your communication and campaign results. There’s no contracts required and no hidden fees. All pricing is volume-based, so that you only pay for what you need. And in case you have a problem, we offer quality support that quickly and efficiently answers questions and solves any issues.
Not sure we’re the right company for you? No problem! Start a free trial to see why so many customers prefer Esendex’s Phone Verify over other API. We offer free phone number and carrier lookup credits for first time customers.

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Texting API designed to send & receive SMS & MMS globally using a short code or 10DLC number.

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Easy to use SMS software that can send & receive SMS & MMS using a short code or 10DLC number.

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Powerful voice API that sends mass automated phone calls quickly to mobile & landline devices.

Verification API
Verify mobile & landline numbers, find service providers, & define time zones to restrict calling times.

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