Top API developer interview questions to hire the best API developers for your company

Ask these questions to an API developer for hire

Are you looking for an API developer for hire? However, onboarding a new candidate to be a part of your development team is an exhausting task. Sifting through resumes and conducting one-on-one interviews can take weeks or even months. This delay can set you behind and can critically affect your business. For instance - cost overruns, time overruns, contract termination, etc. - are some of the effects that you are likely to face. So, it would be in your best interest to hire API developers quickly and efficiently but without compromising quality.

We have compiled a detailed list of questions that you can ask an API developer to ease your recruiting process. These questions will assist you and bring you closer to making that perfect hire as soon as possible. However, before you start investing in an API developer, you should first understand exactly what an API developer can do for your business.

What is API development?

API - Application programming interface is one of the most vital components of application development and software systems. API is primarily used for simplifying software development and enabling data exchange between applications through seamless integration. Its major functionalities include organizing code, hiding complexity from the developers, ensuring reusability of components, and extending systems for development.

The application programming interface enables products and services to interact, harnessing each other’s functionality and data via a structured interface. The use of API has multiplied in the last few years. Today, the most popular web applications utilize APIs to create dynamic functionality based on custom business requirements.

The application programming interface serves as a link between the application and the web server. It is an intermediary layer responsible for processing data transfer between the different systems and system modules.

What does an API developer do?

It is the job of an API developer to ensure that the two applications communicate with each other without any hassle. API developers empower applications to share their data with other systems to ease the user experience without needing developer interference. Before we delve further and discuss API-related interview questions, let's see the critical responsibilities of an API developer:

  • Analyze, design, develop, and implement API test automation for various data-driven applications
  • Review project proposals, API documentation templates, testing methods, and automation testing services and come up with estimates and recommendations to design and define system specification
  • Take over the provision of application maintenance and support, setting API testing process and sometimes performing API testing manually
  • Perform API testing to verify the quality of the product
  • Identify, analyze, prioritize, and resolve problems quickly and efficiently for improved performance
  • Establish, participate, and maintain associations with cross-functional teams and stakeholders for project status, architectural and technology trends, risks, functional & integration issues, and update activities.
  • Deployment of application code and configuration across environments
  • Work with SQL servers, graphical user interface, and related technologies for data migration and transformation support
  • Offer guidance and support to the junior team members for effective and efficient development
  • Provide API and web service and precise & updated documentation for future reference

Factors to consider before you hire API developers

API is essential if your organization upholds the idea of “one source of truth.” One API integration correlates to one gateway to data access. Internally, as a business operation, you can connect different applications, and as a result, you have data traveling seamlessly across various departments.

On the other hand, externally, APIs can be utilized to integrate with third-party applications to extend functionality and improve user experience. However, before you start interviewing candidates, it is essential that you first clear up your goals and objectives. Not all API developers would be able to offer what is required to succeed in your technical projects.

So, understanding what your project needs is essential to a successful hire and guarantees efficient technological development, and consequently, a profitable business.

1. Are you looking for a short-term or long-term project?

Before looking for API developers, it is vital to evaluate your project requirements. This usually depends on the budget, resources required, business impact, and project scope. All these factors help the project manager determine how much time is needed to meet the desired outcomes.

A great emphasis should be given on deciding about project governance. Establishing the type of project earlier not only helps you hire the right API developers but also prevents miscommunication, misunderstandings, and cost overruns later.

2. Do you need a full-time or part-time API developer?

Any software development process requires a time commitment from ideation to design and development to deployment. After deployment, developers need to put continuous effort into maintenance and ensure the application is up-to-date. That being said, whether you hire a team of API developers or a single API developer, achieving the desired outcome can be difficult sometimes.

If you have a constant flow of API-related tasks that need to be cleared on priority then you should start considering hiring a full-time API developer. A full-time developer will help fill the gap in your existing team and contribute to creating and maintaining API as needed for sustainable business growth.

Alternatively, if you have a specific gig that requires a particular skill set or the API lifecycle management in your company is not extensive, or your existing team lacks proficiency to create and maintain APIs then you can consider hiring a part-time developer. You should choose a part-time API developer who will complement and blend well with your current development team.

You should also evaluate and consider if you require an in-house, remote, or freelance API developer. However, this decision depends on various factors like budget concerns, scope of your project, current project status, etc.

3. What type of API does your project need?

Before you look for API developers for hire, it is better to understand the technology. It is important to know the different types of APIs to help you choose the most compatible API that would be beneficial for a successful project.

However, you don't need to necessarily decide right off the bat which type would be the best fit. You're hiring an API developer to do that work for you. Nonetheless, it does give you some idea about the technology and assists you in hiring an API developer with the right skill set and experience. So, four widely agreed-upon types of web APIs that your project might need are:

  • Open APIs: Also known as public APIs or external APIs, Open APIs encourage third-party integration. Basically, it enables API developers to connect and access third-party software for their solutions. For instance, You can hire Google API developers to establish communication with Google Services, including Search, Gmail, Translate, Google Maps, etc. If you want to extract and leverage data and functionality from the Facebook platform, then you should hire Facebook API developers. Similarly, you should hire Amazon API developers if you wish to access Amazon's product catalog data.

  • Partner APIs: These APIs are shared externally among companies with an existing business relationship. Here API developers have better control over who can access your resources and how they will be utilized. With limited access to authorized clients, partner APIs offer robust security measures.

  • Internal APIs: Unlike open APIs and partner APIs, Internal APIs are used to make your internal operations seamless and more productive. Internal teams can share tools and request data for smooth business operations. Additionally, it enables API developers to set up improved security, better access controls, and finer traceability.

  • Composite APIs: These APIs allow API developers to combine multiple API requests into a single API call. It is highly beneficial in a micro-service architecture. It simplifies extracting data from different applications or data sources, significantly reducing server load.

4. What is the budget of the project?

The key to successful software development, or API development, is avoiding the pitfalls that hinder successful development. One of the ways you can avoid these stumbling blocks is budget planning. It is a crucial step that allows you to estimate the cost of completing each project activity over different project phases.

Consequently, enabling you to accurately set expenditure expectations and ensure that the investment of time and effort results in success. Precise budgeting assists API developers in figuring out the project variable and translating them into budget-driven deliverables. It also helps in outlining workflows that are aligned with the available resources.

So, when you're seeking API developers for hire to be a part of your development team, you must curate a proper project budget. The trick to optimizing the development processes is to prevent overspending while maintaining quality.

5. How will you compete with other companies in hiring the top API developer?

API developers are in high demand in today's digital world. Businesses across the world are now leveraging APIs to accelerate their business, streamline operations and deliver a better overall customer experience. They now rely on APIs for various critical business operations.

For instance, API developers can effectively harness API capabilities to add navigation features into your application, authorize users' bank account details, integrate records with third-party billing services, and so on.

The demanding conveniences enabled by APIs and changing business needs have forced companies to invest in APIs and develop API-driven applications. This cutthroat competition might restrict you from attracting experienced and competent API developers to your development team.

Therefore, you need to consider how your proposition stands out from the crowd seriously. Additionally, you need to pay attention to establishing your values or merits as an employer.

Top API developer interview questions you should ask before hiring them

Before you decide to hire API developers, it is important to evaluate their skillset to ensure that they are the right fit. You can do this by asking relevant questions as follows -

1. Have you worked on similar projects?

An API developer does not necessarily need to have experience in the specific field that your business specializes in. Nevertheless, prior experience is always a good idea as they can effortlessly adapt to the environment and quickly get started with the project. Therefore, when you seek API developers for hire, you should definitely ask this question as it helps you understand the previous experience of the API developer.

2. Can you show me your portfolio, references, or previous client testimonials?

This is one of the most important API developer interview questions to ask as it would allow you to go through the portfolio of developers. Portfolios are one of the best ways to evaluate the candidate's competencies. It is a window that reflects their accomplishments, skills, experiences, and attributes.

References help you access the candidate's potential for success in the position by validating the details, including - skills, performance, knowledge, and work history. And lastly, if possible, you can look for client testimonials. Their reference will be most valuable in evaluating the candidate's capacity to help meet your unique business needs. However, when an API developer refuses to showcase their portfolio and share their past client's experiences, consider it a red flag and avoid onboarding such developers.

3. Do you understand the business model?

An API developer must understand your business model and target audience to develop solutions that will improve user experience. So, if you don't wish to risk a failed project, you should ask this question about your business requirement and how the developer would help in facilitating solutions to it through seamless API integration. You should choose to hire an API developer who understands your business approach and knows what your customers need.

4. How will you ensure consistent communication?

You need to ensure a consistent communication channel is in place for regular quality feedback to keep the API developers on track and moti­vat­ed to achieve their objec­tives. This is why you should ask this question about their communication and collaboration skills. The candidate’s answer to this question will determine will give you a good idea of how they will blend into the team.

5. What methodology do you use for API development?

Last but not the least, this is one of the most important API developer interview questions to ask. The answer to this question can assist you in gauging the candidate's compatibility across your system. For instance, if your business uses Agile methodology; then the API developer should be able to efficiently embrace the same. This ensures that you and the candidate are on the same page for your API-specific development project.

6. What are the different API protocols?

Asking this question will help you understand the developer’s level of proficiency in API development and their grasp on the subject. Since the use of APIs in web applications has become prominent, several protocols have been introduced for outlining the acceptable commands and data types. These protocols provide the underlying standards for exchanging data and information between different software applications. Some of the major application programming interface protocols used in the industry include SOAP, REST, JSON - RPC, and XML - RPC.

7. What are the different types of API testing modules?

Testing is one of the most important criteria for any software development project. This question will help you understand the developer’s knowledge and experience on different API testing scenarios and how well they can handle the testing of your API development project.

API testing is a vital process that ensures that the APIs are not only functional but also highly secure and reliable. The different API testing modules commonly used in the industry are validation testing, runtime error detection, functional testing, load testing, penetration testing, UI testing, WS compliance testing, and fuzz testing among others.

8. How will you ensure API security?

This is a vital question related to API development as it deals with the security of application data. The answer to this question will help you understand the developer’s expertise in security protocol implementation and thus ensuring overall security of your API project.

A robust API security mechanism is critical since it is responsible for connecting two different components of applications and thus can be vulnerable to potential outside threats. This is why the calls made by API consist of authorization credentials for minimizing the threat of security attacks. The APIs also use cookies, string parameters, or HTTP headers to provide additional security layers to the transfer of data and communication.


If you want to hire reliable and highly efficient API developers, it would be better to do thorough research by making a list of interview questions on APIs to hire the best candidate for your development team. However, if you don’t want to go through the hassle of conventional hiring, then you can choose the services of deep jobs platforms like Turing. Turing helps you find skilled remote API developers smoothly within 3-5 days. Turing allows companies to tap the world's untapped human potential and ensure that you get the right candidate to lead and oversee your project.

All you need to do is share your requirements with us and we will help you find the top-rated developers that fit your project. Join hundreds of companies that trust Turing to hire remote API developers.


  • Anupriya Singh

    Anupriya Singh

    Anupriya is a content writer well-versed in researching and writing on an array of topics. She works closely with businesses and helps them get rapid and organic growth through compelling digital marketing content. When not working, you can find her reading or sketching.

Frequently Asked Questions

The best way to interview a good candidate is by asking the right questions so that you can effectively decide whether the candidate has the right mindset and skills for the role you are offering. For that you have to prepare thoroughly before taking the interview.

The Payload is the body of your request and response message. When you make an API request, it contains the data that you send to the server. The payload can be sent and received in a variety of formats, including JSON.

The API tester's role is to perform testing to ensure that the API provides the expected functionality, security, performance, and reliability. Tests are run on the API directly or as part of integration testing.

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