React Native is developed by Facebook. The open-source, single-threaded framework allows React Native application experts to build cross-platform mobile apps using JavaScript.

React Native engineers in the U.S. earn $121,875 a year on average with the highest number being $155,000 a year. Thus, when you hire a React Native developer, you must make sure they are worth the investment.

In the next sections, we will discuss the kind of questions you need to ask before you hire a dedicated React Native developer to make sure they are the right fit:

  • 5 technical questions to ask

  • 5 exploratory questions to ask

5 technical questions to ask to hire a React Native developer

Before you hire a React Native developer, you must be certain the developer has sound technical knowledge. Here are 5 questions to figure out the same.

  • 1
    Tell me the difference between React Native and ReactJS.

    A good React Native developer would know the below-mentioned differences between the React Native framework and ReactJS:

    • Scope of use: React Native is the framework for developing mobile apps with a native feel. ReactJS is a JavaScript library for creating responsive user interfaces for web apps.

    • Routing mechanism: React Native offers an in-built navigator library for navigating mobile apps. ReactJS doesn’t have an in-built routing ability and instead uses a react-router.

    Before you hire a dedicated Native app developer, make sure the developer knows these differences.

  • 3
    Describe the different threads in React Native with the usage of each.

    The top React Native app developers know the React Native framework uses 3 threads:

    • Shadow thread: Shadow thread is a background thread that calculates the layout created using React library in React Native framework.

    • Javascript thread: This thread executes the main JavaScript code.

    • MAIN/UI thread: This is the primary application thread that runs the Android or iOS mobile application. The MAIN/UI thread can change the user interface of the app.

  • 3
    What causes performance issues in React Native?

    A skilled React Native developer would know the real issue behind poor performance in React Native is that each thread is too fast. Furthermore, a competent React Native developer would expand the answer by saying the issue mostly occurs when you pass components from one thread to another more times than necessary.

    The best React Native developers would also tell you keeping the passes over the bridge to a minimum significantly lowers performance issues in React Native.

    If a developer answers in these lines, hire those React Native programmers.

  • 4
    What is a memory leak in React Native? How can you spot and fix the issue?

    A skilled React Native developer would tell you when the Garbage Collector (GC) encounters a section of the graph that is not referenced directly or indirectly from root objects (such as variables on the stack or global objects like window or navigator), a memory leak occurs.

    Furthermore, a competent developer would know the React Native framework attaches each JS module scope to a root object. The modules declare variables kept in the main scope. Thus, such variables retain other objects and prevent memory leaks.

  • 5
    Explain Redux.

    A good React Native developer would know Redux is a predictable state container for JavaScript apps.

    Furthermore, the top developers would know Redux helps developers write applications that run in different environments. Thus, the complete app data flow is handled within a single container while persisting at the previous stage.

5 exploratory questions to ask to hire a React Native developer

If you want to hire a React Native developer, you must make sure they have not only the technical knowledge but the correct mindset, leadership and communication skills, and a team player mentality. Here are 5 exploratory questions to help you figure out.

  • 1
    What if one of your colleagues doesn’t improve even after offering continuous feedback? How will you tackle the situation?

    The goal of the answer is to assess the developer’s leadership abilities. A skilled developer would firmly tell their colleagues what is going wrong. However, the developer would be humble and respectful in the approach.

    If the candidates answer in these lines, hire those React Native app developers.

  • 2
    What if your boss doesn’t approve of any of your decisions but it is beneficial? Will you stand by your decision or agree with your boss?

    A competent React Native developer would not be a conformist. The developer would stand their ground and advocate for implementing decisions that are beneficial for the project.

    The developer would also maintain decorum, offer logic and reasoning as to why the implementation is necessary, and don’t get personal while standing by their own decisions.

  • 3
    Mention a time when you designed new features to make an app faster. How did you do it?

    The answer to this question would demonstrate the competence of the React Native developer. Focus on whether the developer explains the specific ways in which they designed the new features.

    Furthermore, a developer could broaden the answer by mentioning the obstacles they faced along the way, how they overcame the obstacles, and what they learned from the experience.

  • 4
    Describe the most interesting project you participated in? Why was it interesting?

    The answer would tell you what the developer’s area of interest is. A good answer would describe the project details, the specific role of the developer, and the contribution they made to the project.

    Furthermore, the best answers would mention the collaborative efforts and how each team member helped the developer.

  • 5
    Share a time when you had to work under pressure. How did you manage the situation?

    The goal of the answer is to assess how the React Native developer handles complex projects, tight deadlines, and stress.

    The best answers would mention assessing the situation quickly, figuring out the ways to cope with the work pressure, and implementing the methods successfully without feeling overwhelmed.