Roblox Software Engineer Interview Guide

Updated a month ago by Roblox candidates
Written by Charlotte Bush, Senior Technical Contributor

The gist

Roblox is more than a game—it’s an open-world ecosystem with an in-game economy and a vibrant culture. The Roblox platform is revolutionizing the way tens of millions of daily users interact online, and as it scales up to a billion daily users, Roblox’s software engineers work to ensure its users are secure and engaged.

The interview loops at Roblox are team-independent, so there’s variance among each team’s process. However, what remains true throughout the teams is that Roblox tends to prefer software engineers with experience in at least some of the following:

• Performance optimization (preferably in Lua, or a similar language)
• Large-scale hosting infrastructure
• Machine learning
• Cloud services
• Rendering systems

What does a Roblox Software Engineer do?

Some major advantages of being a Roblox Software Engineer are increased ownership and direct impact. Engineers on user-facing teams appreciate how quickly they can see the changes from shipped code and effectively get user feedback in real-time.

Typically, Roblox engineering teams are focused on user-facing or internal development. Software engineers at Roblox may be hired to work on anything from building moderation tools to iterating on 3D avatar technology to building the machine learning that makes the Roblox environment adaptive.

The average total compensation across software engineering levels at Roblox are:

• (Entry-level) Software Engineer: $241K
• Software Engineer: $295K
• Senior Software Engineer: $399K
• Principal Software Engineer: $672K

Before you apply

• Spend time in Roblox: Many of your interviews may be formatted as games on the Roblox platform, so you’ll want to know your way around.
• Sharpen your problem-solving and behavioral skills.
• Get comfortable with machine learning and cloud infrastructure.
• Research the recent interview questions asked at Roblox.

Interview process

Though Roblox teams have differing processes, applicants generally describe four interview stages, split into at least five conversations:

1. Recruiter phone screen to ensure you meet the minimum requirements for the role.
2. Technical screen, which is usually done on CodeSignal.
3. Onsite interviews of at least four hours coding whiteboards and behavioral interviews.
4. “Bar Raiser” interview, which is a unique feature designed to test what Roblox values most: problem-solving (in this case, system design) and behavioral skills.

1. Recruiter interview

In this typically thirty-minute call, there may be some light technical questions, but usually not. The focus is on behavioral questions and typical recruiter logistics questions.

Be ready to talk about your previous work history and skills as they relate to the job description and why you’re passionate about game design, scalability, and virtual open worlds (aka “why Roblox”).

Sample questions include:

• Walk me through your resume.
• Why Roblox?
• Are you a gamer? What can you bring to our game?
• What are you looking for in your next role?
• Do you have salary requirements?
• Do you live near San Mateo, California, or are you able to move?

2. Technical screen

Roblox technical screens are typically 60–90 minutes, and depending on the seniority of the role you interview for, here’s what you can expect:

• Interns and entry-level candidates do a short coding round on CodeSignal, then a cognitive assessment designed to test situational awareness and systems thinking.
• Mid-level individual contributors complete a more involved CodeSignal task.
• Senior-level and Manager roles typically get a system design interview. (Note: the system design questions asked in this interview will be easier than the ones you’ll be asked in the next phase.)

CodeSignal

Roblox’s technical screens are conducted on CodeSignal, and for entry-level and mid-level applicants, questions can involve:

• Coding
• Hash Maps
• Sorting
• Search
• Strings
• Graphs

Sample questions include:

• Given a string s, check if it can be constructed by taking a substring of it and appending multiple copies of the substring together.
• Given an unsorted array of integers and an integer k, find the number of subarrays whose sum equals k.
• Code a bouncing diagonal in a graph.
• Describe how a hash table achieves its lookup performance.
• Create a breadth-first search using a queue to search all of the closest elements in a grid.

Cognitive assessment

Entry-level and internship candidates will be guided through a real-world scenario and given a number of tasks to complete in a 3D interactive environment built on Roblox. Roblox hiring managers stress that “there are no right or wrong answers here; rather, we’re simply looking to understand how you approach solving problems.” The assessment tracks the actions you take and then uses data science to score you based on the observed decision-making process, as well as your results.

Sample questions include:

• Use a decision tree to find which deer will be infected (i.e., find the rules of infection) by disease after time 3 based on deer weight, deer age, humidity, and temperature (4 different combinations).

System design interview

In this system design interview, you’ll have an hour to answer a prompt. Applicants report these questions being more general, while the system design questions in the later onsite stage are more specific to game design.

Sample questions include:

• Design a text editor with a cursor that can do the following:
  • Add text to where the cursor is.
  • Delete text from where the cursor is (simulating the backspace key).
  • Move the cursor either left or right.
• How would you approach the design of a platform like Instagram?
• How would you go about designing a chatbot service?

3. Onsite

Applicants report that these 4 to 7-hour sessions are the hardest and most open to variation of any hiring stage at Roblox.

These sessions are broken into three stages:

1. CodeSignal problems
2. System design
3. Behavioral

CodeSignal

You have an hour to complete two CodeSignal problems, which increase in difficulty. Timing is strict at this phase, so be ready to solve both problems efficiently.

Topics include:

• Dynamic programming
• Matrices
• Optimization and test case design
• Arrays
• Hash Maps

Sample questions include:

• What is a virtual function, and how is it implemented?
• How would you implement various data structures in LUA that exist in the Java standard library?
• Implement an LRU Cache.
• Given two strings, s and t, of lengths m and n respectively, return the minimum window substring of s such that every character in t (including duplicates) is included in the window.
• Rotate the non "X" values in an odd n x n matrix a given number of times.
• From a m x n matrix, read the matrix in a spiral way (top row, right column, bottom row, left column...) and print a flat array.

System design

For candidates at and above the senior level, Roblox typically splits this 60-minute round into two phases: one standard system design question and one deep dive into a system you designed previously. Candidates below the senior level will only go through the first phase.

Sample questions include:

• How would you set network protocols while designing a game?
• How would you integrate in-game messaging while designing a 3D game?
• How are caching and sharding techniques applicable in game development?
• What are some common challenges and solutions for minimizing lag and ensuring smooth gameplay in multiplayer games?

Behavioral

You’ll have at least an hour of behavioral questions, with higher-level candidates having as many as three separate hour-long sessions.

Thematically, these questions will focus on group problem-solving strategies and interpersonal skills.

Expect your interviewers to pick one project on your resume and drill down into the details. Be ready to reflect on why you made development choices and used certain tools. Discuss in detail what you learned and your work style during the course of the project.

Sample questions include:

• Have you ever had a disagreement with a team member? How did you overcome it?
• Describe a time a member of your group didn’t pull their weight. How did you address it?
• Tell us about a time when you faced pressure to deliver on a difficult project.

4. “Bar Raiser” interview

Your final interview at Roblox will be an hour-long Bar Raiser interview, a format that few companies employ. Think of the Bar Raiser as a combination of a behavioral and system design interview. You’ll be given a question—usually based on a technical problem Roblox has faced in the past—designed to get you out of your comfort zone. Though you're talking about technical subjects, the way to score points is by broadcasting a signal of Roblox’s Core Values:

• Respect the Community — We consider our impact on the world, strive to make decisions with everyone’s best interests in mind, and communicate authentically. We prioritize our community before company, company before team, and team before individual.
• We are Responsible — We are empowered and responsible for both the intended and unintended consequences of our actions.
• Take the Long View — We drive innovation by setting a long term vision, even when making short term decisions.
• Get Stuff Done — We drive execution every day by taking initiative and relentlessly iterating towards long-term goals.

Additional resources

• Take our Software Engineering Interview course to level up your role-specific interview skills.
• Get coaching and actionable feedback from software engineers at the level you aspire to land an offer for.
• Practice with mock interviews on the most common types of problems and interview questions.

FAQs

What can I expect from my interview at Roblox?

Relative to other big tech companies, Roblox focuses more on behavioral and problem-solving questions, weaving them into every stage of the hiring process. Candidates may have at least seven interviews before receiving an offer.

On average, how much do Roblox Software Engineers typically make?

The average total compensation across software engineering levels at Roblox are:

• (Entry-level) Software Engineer: $241K
• Software Engineer: $295K
• Senior Software Engineer: $399K
• Principal Software Engineer: $672K

How long is the typical Roblox interview process?

On average, it takes 6–8 weeks, though some candidates report it taking as long as 3 months.

How should I prepare for a software engineering interview at Roblox?

• Play Roblox’s practice assessment, Kaiju Cats, to get a sense of what the Cognitive Assessment may be like and familiarize yourself with the platform's UI.
• Familiarize yourself with Roblox’s Core Values, and practice broadcasting a signal of those values. That way, your interview answers will reflect the ideas Roblox is looking for.
• Study up on large-scale hosting and rendering systems.
• Spend time as a developer on the Roblox platform. This will help you better answer the System Design and Bar Raiser questions and will also help you stand out as a candidate.

Will I have in-person interviews?

Yes, since Roblox has mandatory in-office hours for at least three days a week for all new hires.

Do I need to be a Roblox developer to get a job at Roblox?

No, but using a Roblox developer account as a supplementary portfolio does help show the hiring team that you’re familiar with the environment and conversant in the tech stack. Roblox’s Chief Scientist, Morgan McGuire, says this is "... an awesome way to just say 'this is something I'm passionate about, and I'm using it to learn new skills.'"