Discord Software Engineer Interview Questions

Discord·Software Engineer·Onsite - System Design / Architecture

Jul 2026

Discord system design round for a software engineer role. The whole thing was one big deep-dive into building a Slack-style chat system, and they clearly wanted more than a surface-level answer. Covered a lot of ground fast.

Design a workspace-based chat system with channels, direct messages, real-time delivery, message history, edits, deletes, typing indicators, read receipts, and presence.

“This is a beast of a question.”

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Discord·Software Engineer·Technical Phone Screen

Jul 2026

Phone screen for a Software Engineer role at Discord, focused entirely on building an async TCP chat server in Python from scratch. Two-part problem: a global room first, then rooms with command parsing. The concurrency angle was the whole point.

Build a TCP chat server using Python's asyncio that handles up to ~1000 concurrent clients over a line-based text protocol, starting with a single global room where all clients share one broadcast space.
Extend the chat server to support named rooms and slash commands: /join to switch rooms, /who to list room members, and /quit to disconnect cleanly.
How would you scale this chat server horizontally so users in the same room across different server processes can still see each other's messages?
How would you handle a slow or stuck client whose socket buffer is full without blocking message delivery for everyone else?
How would you implement graceful server shutdown so in-flight writes finish and connected clients get notified before the process exits?
What strategies would you use to bound memory usage and prevent abuse, such as from very long lines, too many rooms, or high message rates?

“The hardest part wasn't the code, it was knowing what to ask before writing anything.”

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Discord·Software Engineer·Technical Phone Screen

Jul 2026

Discord data engineer round, pretty much one meaty SQL question with a follow-up that caught me a bit flat-footed. Technical phone screen vibes, focused entirely on time-series aggregation.

Using a server_view table with columns for server ID, user ID, and timestamp, write a SQL query that calculates week-over-week change in server views across the past 12 months. For each ISO week, return both the absolute and percent change compared to the prior week.
How would you handle weeks with zero views so they still appear explicitly in the output rather than being silently dropped? Walk through using a calendar/spine table or generating a week series to fill gaps.

“I got the core aggregation down fine, LAG() over the weekly partition, pretty standard.”

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Discord·Software Engineer·Onsite - Behavioral / Leadership

Jul 2026

Behavioral round at Discord for a software engineer role, pretty focused on depth over breadth. Just one question but they really sat in it with you.

Walk me through a project you're proud of. What was the problem, what did you personally contribute, what technical decisions did you make and why, and what was the actual impact?

“This sounds like a warm-up but it's not.”

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Discord·Software Engineer·Recruiter / HR Screen

Jun 2026

Interviewed for a data engineer role at Discord, and the only question I can really speak to is the classic 'why do you want to work here' opener.

Why do you want to work at Discord?

“I had an answer ready but it still felt a little hollow when I said it out loud.”

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Discord·Software Engineer·Technical Phone Screen

Jun 2026

A one-hour technical round for a Data Engineer role at Discord that was basically a Python data design exercise. Nothing crazy algorithmic, but the problem had enough moving parts that I kept second-guessing my structure halfway through.

Design a dictionary structure to represent a game's information (name, genre, country, release date) and its associated Discord servers, where game data should be sourced from something like Wikipedia.
Given a list of game dictionaries, implement a function get_genre(input_game) that returns the genre for a given game name.
Implement get_games(input_genre) that returns all games belonging to a given genre.
Implement get_most_available_games(games) that returns the game or games with the highest number of platforms.
Implement get_available_games(number_of_platform) that returns all games available on exactly that number of platforms.

“This felt more open-ended than I expected.”

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Discord·Software Engineer·Technical Phone Screen

Jun 2026

Discord data engineer interview with a SQL-heavy technical screen. Just the one question from what I remember, but it was more involved than it looked on the surface.

You have a server_view table with columns server_id, user_id, and timestamp. Write a SQL query to find the average number of weekly server views for the year 2020. You need to aggregate total views per ISO week first, then average those weekly totals.

“Took me a beat to realize they wanted two layers of aggregation, not just a single GROUP BY.”

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Discord·Software Engineer·Technical Phone Screen

Jun 2026

Senior systems role at Discord, two back-to-back low-level C++ questions that felt more like a grad-school exam than a job interview. No fluff, just fundamentals, and they went deep fast.

Walk me through memory alignment and padding in C++, including how struct member ordering affects sizeof and what real problems misalignment can cause.
What is an ABI, how does it differ from an API, and why is C++ ABI stability such a persistent problem compared to C?

“I knew the basics but fumbled the example on the spot.”

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Discord·Software Engineer·Recruiter / HR Screen

Jun 2026

Behavioral screen for a SWE role at Discord. Just one question about motivation for getting into engineering, nothing technical.

Why did you want to become a software engineer?

“Pretty standard opener but I still fumbled it a bit.”

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Discord·Software Engineer·Onsite - Coding / Algorithms

Jun 2026

Discord SWE interview where I prepped the wrong thing entirely. The coding round was way more hands-on than I expected, basically pair programming a distributed systems problem from scratch with the interviewer sitting next to you (virtually) the whole time.

Implement a leader-follower distributed system locally. Nodes should know who the current leader is, support new nodes joining, and handle automatic failover with leader re-election when the leader goes down.

“I had spent a solid chunk of prep time on a chat server design I'd seen floating around, so when this came up I had to context-switch pretty fast.”

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