CodeSubmit Interview Series

11 Best Full-Stack Interview Questions in 2023

Want to hire your next full-stack web developer? Looking for the best full-stack interview questions to use in your interviews? You’ve come to the right place. Read on to get our top interview questions for full-stack developers.

Full-stack interviews

Full-stack web developers develop both client and server-side software. Full-stack developers typically master HTML, CSS, plus languages and frameworks such as JavaScript, PHP, Python, C#, Ruby, Java, Node.js, Django, or Angular.js. Preferably, they will also need to have basic design skills and an understanding of website architecture and database storage. 

But as full-stack developers need to have a vast understanding of different tech skills, how do you ensure that you choose the right candidate? That’s what these interview questions will help you with. 

Beginner full-stack interview questions

First up: interview questions for junior full-stack developers. These interview questions give you an understanding of how well candidates understand the benefits of full-stack development and their role as developers in your team.

1. What is full-stack development?


Full-stack development is the development of frontend (client-side) and backend (server-side) web application portions. Full-stack developers can design web apps and websites from start to end. They work on the frontend, database, backend, and debugging of web apps or websites. 

2. What programming languages are you comfortable with? 


One of the first things you’ll want to understand is what languages full-stack developers are proficient in. Full-stack developers should know HTML and CSS, as well as other languages and frameworks such as JavaScript, Python, or PHP. Or, depending on the industry, your developer may need or have experience with more specific use-case languages, like Erlang or Lua.

3. What’s an example of a project you worked on and the tech stack you used. Why did you make these choices? 


It’s key that a full-stack developer can justify the tech choices they make and understand the methodology of full-stack web development. You’ll ideally look for a balance between front-end and back-end development; however, candidates can have more experience on one side and that’s fine, as long as they demonstrate that they can work on both ends of the application. 

4. What is DevOps?


If you use DevOps, you’ll want to understand how well candidates understand this practice. DevOps emphasizes the collaboration and communication of software developers and other IT staff to deliver software products faster and lower the failure rate of releases.

5. What is multithreading? 


A thread is a set of instructions that can be executed at the same time as other threads, which are part of the same root process. Multithreading, on the other hand, is when a CPU executes multiple threads within a program at the same time by using the same processing capacity. 

Advanced full-stack interview questions

What are some advanced full-stack interview questions? Here are the top questions to ask senior full-stack candidates. The specific questions you ask depend on what languages you require candidates to know or, if you don’t have specific requirements, what languages they do know. You can find more language-specific questions on our pages:

  • Node

  • PHP 

  • DevOps

6. What is an event loop in Node.js? How does it work? 


All async callbacks are handled with an event loop. In other words, when a listener is attached to an event and the event fires, the listener executes the callback. 

When setTimeout, http.get and fs.readFile are called, Node.js continues these operations and other code without waiting for the output. However, when the operation finishes, it receives the output and runs callback functions one by one. 

7. What are the main errors in PHP? 


There are three main errors in PHP. These are: 

Notices: Non-critical errors that happen during the script execution. For example, accessing an undefined variable.

Warnings: More important errors, but scripts continue the execution. 

Fatal: This error causes a termination of the script execution. For example, this can happen if someone accesses a property of a non-existent object or require() a non-existent file. 

8. How do you approach a DevOps project?


A DevOps project can be approached in the following way: 

Stage 1 

First, start by assessing the existing process and implementation for 2-3 weeks to identify areas of improvement. The team then comes up with a roadmap for the implementation.

Stage 2

Create a proof of concept and approve and accept it. The team then starts implementation and rolling out the project plan.

Stage 3

The project is ready for implementation of DevOps by using version control/integration/testing/deployment/delivery and monitoring. 

9. What is namespacing in JavaScript? Please define.


Namespacing makes it possible to group functions, variables, and more under a unique name. This improves modularity and makes it possible to reuse code. 

10. What are the benefits of Python?


Python supports readability and that way, program maintenance can be reduced. It includes high-level data structures, dynamic typing, and dynamic binding, which makes it a popular choice. And Python can be used to script, it’s open-source and it supports third-party packages. 

11. Explain how Java enables high performance.


Java makes use of the Just-In-Time compilation, which means that required code is executed at run time by translating bytecode into machine code. Then, the code is executed directly. 

The Just-In-Time compilation is enabled by default in Java. It gets activated when it’s called, so that it compiles bytecode into native machine code. The compiled code is called directly instead of being interpreted, which ensures the performance boost. 

Over to you!

There you have it! Now you know how to use these full-stack interview questions in your interviews. What it comes down to is that you ask questions that show you not only what candidates know, but how well they communicate that knowledge and how open they are to learning. 

That said, interviews are only part of the equation. Another part is developer skill assessment tests. 

CodeSubmit offers market-leading assessment tests. 

Want to try them today? 

Sign up for a free CodeSubmit trial! (No credit card required.)