Truecaller delivers an experience that goes beyond the limitations of today’s phonebook apps so that people always have access to the right information, people and businesses they need. It lets you search for contact information (based on name or number), identify incoming calls, and block calls you don’t want to receive – so you never have to leave the service to find the right contact.

Started five years ago, Truecaller was an idea of two engineers who aimed to create something new in the world of technology. Today they stand as a company of 55 international minds coming from different corners of the world to make a service that stretches every remote place of the world.

Today, many smart phone users are using Truecaller to trace out a lot of spam calls they get everyday. So, did you ever wonder How Truecaller actually works? How does it know all the phone numbers and caller ids?

How does Truecaller app work?

Truecaller acts on a give and take scenario... You want those unknown numbers then you have to part with your phone book contacts.. Now apparently everyone who has installed the app has surrendered his phone book. The data is crowd-sourced from the millions of users who have downloaded the truecaller app on their smart phones. As part of the end user agreement, the truecaller app asks the user to allow access to the user's address book/contacts on the smart phone. This data is then uploaded by the app to the company's servers. After going through several data matching/refining algorithms, this data is made available to all truecaller users to search upon.

The story must start from the login screen. If you have already used Truecaller, you might have seen that Truecaller only allows either Facebook, Yahoo! or Gmail to access Truecaller app. If you don't have one you cannot connect to Truecaller database. This is because, Facebook, Gmail and Yahoo! are the most widely used social networking sites that contain a lot of phone numbers and other contact details. It implies that when you use one of the social sites, your entire contacts including phone numbers, contact names, email ids will be uploaded to a secure Truecaller server. In case you login to the app using your mobile phones then your entire address book will be sent to the Truecaller servers. These are organized into records and each number will be assigned a Truecaller id. When some one searches the number using Truecaller number search, the caller id associated with that number will be displayed.

So out of all the people who know you and have your contact number stored against your name in their phones - if even 1 person uses the truecaller app, your contact number and name would end up in the truecaller database.

Pros

Allows you to find mobile phone location of the number in phone number search.

'Who viewed my profile' functionality is  also provided by Truecaller application. You can keep a track on who is viewing your number.

You can find caller from phone number. Similar to reverse phone lookup

It allows you to block such spam numbers and report them to Truecaller database to mark it as spam so that others may also not suffer from this number

Cons

Caller ID does not work in all areas

Truecaller requires Internet connection for it to work

No guarantee of information security

It infringes on privacy issues.

How to unlist Number from Truecaller

This is an important feature of Truecaller that lets you to remove your private number from the database. Go to the below link enter phone number that you wish to unlist from Truecaller, select a reason and fill out the captcha then select unlist. Done ! your number will never again be uploaded to the server and previous records associated with your number will be deleted.