Python developers remain in high demand thanks to the versatility and broad usefulness of the language in various domains of business. 

However, hiring a good Python developer is not as easy a task as it might seem. 

When it comes to hiring Python developers, asking the right set of questions and testing them on certain specific concepts can help you determine the applicant’s capability and potential fit for your organization. 

We have a full-fledged guide on how to hire a Python developer that you can refer to if you wish to hire one on your own.

An important thing to keep in mind is that the tech talent shortage is expected to worsen in the coming months in 2023 when people are more likely to quit their 9-5, in-office draining jobs and start a self-employed work life where they choose who to work with. 

This could make it increasingly difficult to find skilled and affordable Python developers who can meet your business needs adequately.

On top of that, finding, vetting, and hiring a qualified Python developer can be a time-consuming and costly process. 

Many companies struggle to find candidates with the right technical background and experience, making it difficult to find the perfect fit for their particular project or job opening. 

Also, without having someone in your organization who has a decent technical background, it can be even more difficult to navigate the job market and evaluate a potential Python developer’s skills and experience.

Regardless, it is essential to ask the right questions when hiring a Python developer to ensure they have the technical capabilities that also align with your company culture. 

To make sure you’re asking all the right questions, here are 16 essential Python interview questions for you to use.

1) What experience do you have developing applications and programs in Python?

While some programmers (self-taught or otherwise) are very enthusiastic about learning and growing with a company, you may want to prioritize a Python developer’s experience based on your own needs.

2) How comfortable are you with different versions of the language (e.g. Python 2 vs 3)?

Many companies are still using older versions of the Python language, such as Python 2.X or even earlier versions. Make sure that your applicant is familiar with whatever version you have in place. 

Conversely, more modern projects and applications may require knowledge of the newer Python 3.X updates, so it’s important to know what technologies the applicant has experience in.

3) Can you explain the principles of Object Oriented Programming and how they apply to Python?

Object Oriented Programming (OOP) is a programming paradigm that uses objects to model real-world entities, making it easier to think about the problem at hand. 

OOP principles in Python include abstraction, encapsulation, inheritance, and polymorphism.

4) Are you familiar with Django and other frameworks, such as Flask?

Frameworks like Django and Flask are popular frameworks for Python that simplify web development. Django is a high-level framework with out-of-the-box features such as authentication, templates, and ORM. 

At the same time, Flask is a microframework that allows developers to build applications quickly using different extensions. Other popular frameworks include Bottle, Falcon, CherryPy, and Pyramid.

5) What are some of the most creative ways you have used Python in a project?

This question will help gauge the applicant’s problem-solving skills and creativity when it comes to using Python. 

It also gives you an insight into what type of projects they’ve been involved in and how creatively and productively they will be able to contribute to your company.

5) How comfortable are you working with data structures in Python (e.g. lists, tuples)?

Data structures are essential for organizing, manipulating, and storing data. Python has several built-in data structures such as lists, tuples, dictionaries, and sets which enable developers to work more efficiently. 

Knowing how to use these various data structures is an important part of being a successful Python developer. This question will help you gauge the applicant’s understanding of Python data structures.

6) Are you familiar with web scraping and other forms of data collection?

Web scraping is a technique for collecting data from websites, while other forms of data collection include APIs, HTML parsing, and database queries. 

Knowing how to use these techniques is essential for any Python developer working with data. This question will help you understand the applicant’s familiarity and level of experience in collecting, manipulating, and processing data.

7) How do you debug errors or problems with your code?

Debugging is an important skill for a Python developer as it allows them to identify, troubleshoot, and fix errors in their code. 

Good debugging practices involve using development tools such as the Python debugger (pdb) and logging functions, as well as understanding common error types. 

This question will help you understand if the applicant has the necessary skills to debug effectively.

6) Do you have any experience using libraries like NumPy or SciPy?

Python libraries are packages of pre-written code that enable developers to quickly build powerful applications. 

Popular Python libraries include NumPy and SciPy, which provide tools for numerical computing, as well as matplotlib, which is a plotting library used for data visualization. 

Knowing how to use these libraries can help developers save time and create robust programs.

7) What is your experience handling asynchronous tasks in Python?

Asynchronous tasks in Python involve executing multiple functions simultaneously, allowing for concurrent programming. 

This can be done using libraries such as asyncio and curio, or by using the multiprocessing library to handle threads and processes. 

Asynchronous programming is an important part of Python development and knowing how to use these libraries effectively helps developers create more efficient workflows.

8) Have you ever written code for web applications using Python?

Having experience writing code for web applications is essential for any Python developer. 

Make sure your applicant has experience or at least an understanding of how to create dynamic and interactive web pages and use frameworks such as Django and Flask to simplify web development. 

Knowing how to write efficient code for the web also gives developers an understanding of browser compatibility, security, performance optimization, and more.

9) Are you familiar with debugging techniques and code optimization?

Debugging is an essential skill for any programmer, and knowing how to troubleshoot problems with code is a must-have for Python developers. 

Techniques such as using the Python debugger (pdb) and logging functions help identify and resolve errors in code quickly and efficiently. 

Code optimization is also important, as it involves writing efficient code that runs quickly and uses fewer resources. Techniques such as using list comprehensions, avoiding unnecessary loops, and optimizing memory usage can all help create faster programs with fewer bugs. 

Asking the applicant about their experience with debugging and optimization will help you understand how they approach coding problems.

10) Do you have any experience with automated testing in Python?

Python developers should have some experience in using automated testing frameworks such as pytest or unittest. 

Automated tests help identify bugs early on, ensure code quality, and allow for regression testing. Developers should understand how to create unit tests for their code, as well as other types of tests such as integration, acceptance, and performance tests. 

Asking your applicant about their experience with automated testing will help you understand the level of quality assurance they can provide for your project.

11) Are you familiar with version control systems like Git?

Version control is an important part of software development and being able to use version control systems such as Git is essential for any Python developer. Knowing how to work with Git repositories, commit changes, and collaborate with other developers on a project is important.

12) Have you ever deployed a Python application to production and handled post-deployment issues?

Deploying a Python application to production requires knowledge of the software stack, from web servers and databases to caching systems. 

It is also necessary to understand hosting options such as cloud providers or virtual private servers, and how to set up appropriate security measures for the application.

13) Do you have any experience working with databases in Python?

Working with databases in Python is a common task for many developers. Knowing how to create, query, and manage data using popular database systems such as MySQL, PostgreSQL, and SQLite can be invaluable when working on projects that need to persist data. 

Libraries such as SQLAlchemy and Django ORM can help simplify the process of interacting with databases and make it easier to write efficient code. 

Additionally, understanding database design principles such as normalization and indexing can help a Python developer create more efficient data models.

14) Do you have experience writing automated tests using frameworks like PyTest or unittest?

Writing automated tests using frameworks such as PyTest or unittest is a valuable skill for Python developers. 

Automated tests help ensure the quality of code and help to identify bugs early on in development. Developers should understand how to create unit tests, integration tests, acceptance tests, and performance tests. 

Additionally, they should be familiar with mocking libraries such as Mock and unittest.mock, which can help to simplify testing by creating mock objects for code that is difficult or impossible to test directly. 

Prior experience with automated testing will improve a developer’s level of quality assurance skills.

15) What strategies do you use to ensure reliability and maintainability of code?

Developers should strive to write code that is both reliable and maintainable. Strategies such as writing well-structured, readable code with meaningful variable names, using comments to document the code, and following best practices when dealing with errors can all help ensure reliability. 

Additionally, refactoring old or inefficient code, avoiding global variables where possible, and using a linter to identify potential issues can all help ensure the maintainability of code. 

Testing the application regularly with unit tests, integration tests, and acceptance tests helps to identify any potential problems or bugs before they are released into production. 

Finally, having good version control practices such as committing frequently and writing meaningful commit messages can help ensure that changes to the code can be tracked and easily reverted if necessary.

16) Are you familiar with security measures for Python applications?

Ensuring the security of an application is essential to prevent malicious attacks and ensure data safety. 

When developing a Python application, developers should use well-tested frameworks such as Django and Flask that provide out-of-the-box security features. 

Additionally, they should be familiar with concepts such as authentication, authorization, and secure coding practices. Developers should ensure that the application is regularly tested for vulnerabilities with tools such as OWASP Zap or sqlmap. 

Finally, understanding the basics of cryptography can be beneficial when dealing with sensitive data and ensuring its secure storage and transmission.

Conclusion

The vetting process of Python developers can be a difficult task. With Python being a major programming language that every tech startup and company needs to have skilled resources for, it is important to ensure that potential candidates have the right skills and experience to do the job. 

Asking the right questions during an interview can help identify if a candidate has the appropriate knowledge and experience for a particular role. If the interview and vetting process is too daunting and overwhelming for you or if you do not have any technical expert or senior engineer on your team, reach out to Gaper to hire vetted Python developers now.