When you are interviewing a React engineer, there are certain questions that can help you determine if they have the skills and experience needed to be successful in your role. Here are some of the most important questions to ask:

1. 1. What experience do you have using React and related technologies? A great candidate should be able to provide examples of their past work and explain their approach to developing with React.

1. How do you stay up-to-date on the latest technologies and best practices in React development? It’s important that a developer is actively learning and staying current on the newest trends in their field.
2. What was the moment where the light bulb went off and you knew you were a react expert?  What did you learn that day?
3. What challenges have you faced while developing with React? Asking this question can give you insights into a developer’s problem-solving skills and how they handle difficult tasks.
4. What techniques do you use to optimize performance in React applications? Performance optimization is an important part of React development, and a great candidate should be familiar with the various methods available for achieving this.
5. How do you approach creating reusable code?