# Hello!

Welcome to Truecaller SDK documentation!

Here you will find answers to all your queries on how to easily integrate Verification via Truecaller feature into your mobile app and mobile sites.

**What is Truecaller SDK?**

Truecaller SDK is a mobile number verification service, which you can use wherever you look to verify your users.

With more than 400+ million users globally, Truecaller is the largest mobile number identity platform.

This means that these 400+ million users who have Truecaller mobile app on their mobile devices, have created their profiles with Truecaller by verifying their mobile numbers, and associating their identity.

Since these users are already mobile number verified, verification via Truecaller enables you to quickly verify/ signup/ login your users, basis their mobile number - without the need of any SMS based OTP, and at the same time capture their mapped user profile.

Along with this, the SDK also gives you an option to verify users who do not have the Truecaller app present on their devices, via the means of a drop call being triggered to the user's device in background

[<br>](https://docs.truecaller.com/truecaller-sdk/why-truecaller-sdk)


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