Aaykar Setu is a free mobile application designed by Piyush Kumar that aims to help taxpayers with their income-tax concerns. It offers a wide range of features that include a chatbot to provide quick solutions to queries, a search engine to locate Tax Return Preparers (TPS) offices across India, and tax calculators to give quick estimates of tax payable.

One of the unique features of Aaykar Setu is its keyword-based search functionality, which allows users to search for specific topics related to income-tax. The app also provides filtered results based on the user's requirements, making it easier for them to find what they need. Users can also access live chat support on weekdays from 10AM to 6PM for any further assistance.

Another interesting feature of Aaykar Setu is the Tax Gyaan game, which is a multiple-choice question-based game that helps users learn about income-tax in a fun and engaging way. The game is divided into four levels - beginner, normal, hard, and difficult - to cater to users of different skill levels.

Overall, Aaykar Setu is a comprehensive and user-friendly mobile application that provides a one-stop solution to all income-tax concerns.