About IIT JEE Exam :

IIT JEE Mains contains 90 questions. Since all the questions are MCQs with a single response, most of the simple online exam software in the market would suit for IIT JEE Mains.
IIT JEE Advanced consists of 2 papers. Each paper has 54 questions and 9 sections.There are 3 different question formats in IIT JEE Advanced as follows.
1. MCQ with a single correct response.
2. MCQ with multiple correct responses.
3. Single digit numerical answer.

3 important things to consider while choosing the online exam software for IIT JEE

1. Partial Marking support :

Few questions in the Advanced exam has more than one correct responses. There are partial marks for partially correct answers. For example, if (a), (c) and (d) are all the correct options for a question, marking all these three will get +4 marks; marking only (a) and (d) will get +2 marks; and marking (a) and (b) will get –2 marks, as a wrong option is also marked.
The online exam software should be able to support partial grading for the questions.

2. Single Digit Answer and onscreen keyboard support :

The second section in Physics, Chemistry, Mathematics has 5 questions. The answer to each question is a SINGLE DIGIT INTEGER ranging from 0 to 9, both inclusive.
Exam conducting board do not provide the keyboard for the students. They have to choose the single digit answer through an onscreen keyboard as shown in the below picture.

3. Easy uploading of Equations :

Most of the questions are equation based questions.
The uploading of equations based question should not take so much of time.
The software you choose should support bulk upload of equations in Latex Format.
Do not choose the software in which you can upload the equations only as images. Uploading of the equations as images provide poor readability to the users..