There are many great apps available for IIT-JEE preparation, but some of the best include:

• Byju’s: This app offers a comprehensive learning solution for students who are preparing for JEE Mains and other competitive exams. It includes video lessons by expert teachers, practice questions, and test series.
• Toppr: This app is another great option for students who are preparing for JEE Mains. It offers a variety of features, including video lessons, practice questions, and test series.
• Unacademy: This app is a great resource for students who are looking for live classes and video lectures from top educators. It also offers practice questions and test series.
• doubtnut: This app is a great resource for students who need help with specific concepts. It offers video explanations of questions, as well as step-by-step solutions.
• JEE Mains & Advanced Prep: This app is a great resource for students who are preparing for JEE Mains and Advanced. It offers a variety of features, including video lessons, practice questions, and test series.

When choosing an app for IIT-JEE preparation, it is important to consider your individual needs and learning style. Some factors to consider include:

• The level of difficulty: Some apps are designed for students who are just starting to prepare for JEE, while others are designed for students who are already familiar with the material.
• The features offered: Some apps offer a variety of features, such as video lessons, practice questions, and test series. Others may focus on a specific area of the JEE syllabus.
• The cost: Some apps are free to download, while others require a monthly or annual subscription.

It is also important to note that no single app will be the best fit for everyone. The best way to find the right app for you is to try out a few different options and see what works best for you.