Today, there are over 5.2 billion distinctive mobile phone users, and companies have used phone verification as a secure way to validate account ownership, drastically reducing losses due to cybercrime and online scammers. Phone number verification has been widely integrated into various industries, including giant corporations and small-scale businesses. To fully enjoy the benefits of this form of validation, developers are building phone verification APIs. After reviewing all the Phone Verification APIs, nine top APIs were found to be worth mentioning: Telesign SMS API, Veriphone API, Twilio API, Botdelive API, Global Telephone Number Information API, Mocean API, Nexmo Verify API, 2Factor Authentication API, and Telesign Voice Verify API. These APIs offer various features such as sending customized texts, random validation codes, password reset, SMS delivery status reports, voice authentication messages, two-factor authentication, and more. The pricing models of these APIs vary, ranging from free to $250/month for the Mega package. The popularity scores of these APIs range from 5.8/10 to 9.4/10, indicating their effectiveness in phone verification. Each API has its unique features, advantages, and disadvantages, making it essential to choose the best one that suits specific needs.