Discord Interview Questions — Page 2

Discord·Software Engineer·Onsite - Behavioral / Leadership

May 2026

Behavioral screen for a software engineer role on Discord's persistence and database infrastructure team. Three questions, all pretty standard for infra, but the on-call one had some teeth to it.

Walk me through your background and how it relates to a persistence or database infrastructure team.
Tell me about a specific project you're proud of. What was the problem, what did you personally deliver, and what was the measurable impact?
Describe an on-call incident you handled from start to finish, including how you communicated during it and what you did to prevent it from happening again.

“Pretty much a 'tell me about yourself' but they steered it hard toward infra.”

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Discord·Software Engineer·Onsite - System Design / Architecture

May 2026

Discord data engineering interview, system design round focused entirely on dimensional modeling for their server activity data. One meaty question that took the whole session, which I wasn't expecting to go that deep on the schema design side.

Design a fact/dimension data model for Discord server activity, given raw event tables for server creation, server views, server joins, and messages. Define your dimension and fact tables, explain your grain choices, how you'd handle slowly changing dimensions for users and servers, partitioning strategy, and what query patterns the model is optimized for.

“This ran the entire interview.”

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Discord·Software Engineer·Technical Phone Screen

May 2026

Discord coding interview where they handed me a massive open-ended project: build a TCP chat server from scratch, Discord-style. The scope was intentionally huge and they explicitly said AI tools were fair game, which was a twist I wasn't expecting. Evaluating how well you use AI is apparently part of the rubric.

Build a TCP-based chat server with slash commands (/help, /nick, /users, /quit), chat rooms with broadcast messaging, reconnection support, message history (last 10 messages on join), data persistence across restarts, and scalability in mind. You can use AI tools.

“The scope of this thing is genuinely absurd for a single interview session.”

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Discord·Software Engineer·Technical Phone Screen

May 2026

Discord software engineering interview with a question about AI tooling in day-to-day coding. Pretty conversational, felt more like a values/process check than a technical grilling.

How do you incorporate AI coding tools like Copilot, Claude, or ChatGPT into your workflow? Where have they been genuinely useful, where have they let you down, and how do you decide when to lean on them versus not?

“This felt deceptively open-ended.”

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Discord·Software Engineer·Onsite - System Design / Architecture

May 2026

Discord system design round for a software engineer role. The whole session was basically one deep problem about distributed leader election with Redis, and they kept pulling on threads until I ran out of things to say.

Design a leader election mechanism for N stateless service instances using Redis leases, where exactly one instance must act as leader at any time.
Even with ownership-checked lease renewal, how does a long GC pause on the leader create a split-brain window, and what actually prevents stale writes from corrupting data?
Walk through exactly what happens when the Redis primary fails over to an async replica that hadn't replicated the lock yet. Two instances now think they're leader. What breaks?
How would acquiring the lock across multiple independent Redis masters with a majority quorum change the safety guarantees, and does it eliminate the need for fencing tokens?
You're seeing leadership change dozens of times per minute. What are the likely causes and what do you adjust?
What clarifying questions would you ask before committing to a design, and what operational signals would you instrument?

“I started with SET NX PX and felt pretty good about it.”

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Discord·Software Engineer·Technical Phone Screen

May 2026

Discord data engineering interview, one big open-ended question that covered data modeling and SQL analytics for video call data. The question had multiple parts and took up most of the session. Felt like a take-home problem compressed into a live setting.

Design a data model for Discord video call analytics. You have both client-side and server-side event logs. The model needs to support a video/call ID, user ID, user country, call duration, join count, rejoin count, and event timestamp. Walk through how you'd structure raw events, cleaned fact tables, and dimension tables for users and countries.
Write SQL to compute, for each country and calendar day, the total number of distinct video calls.
For every date in the database, compute per-country the number of video calls in the trailing 7-day, 14-day, and 30-day windows ending on that date.

“This part felt manageable at first but the 'raw vs cleaned vs dimensions' framing tripped me up a bit.”

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Discord·Software Engineer·Onsite - System Design / Architecture

May 2026

Discord system design round for a software engineer role. The whole thing was basically one big question with a lot of follow-up dives, so if you're prepping for this kind of interview, expect to spend most of your time defending trade-offs rather than just sketching boxes.

Design the chat subsystem for a large-scale messaging app like Slack or Discord, covering end-to-end architecture, and be ready for deep follow-ups on every trade-off you make.
Walk through your core API design for a chat system: sending messages, fetching paginated history, subscribing to real-time updates, and handling edits and deletes.
What data model would you use for workspaces, channels, memberships, and messages, and how would you handle both channels and direct messages in a unified way?
How would you choose a storage backend and partition message data to keep historical queries efficient at scale?
How would you implement real-time message delivery using WebSockets, and how do you manage connections and subscriptions at scale?
Compare write fanout versus read fanout for delivering messages to channel members, and explain how your choice changes depending on channel size.
How do you guarantee per-conversation message ordering and read-your-writes consistency, and how do edits and deletes fit into that model?
How would you approach full-text search over message history in a chat system?
How do you handle hot channels or extremely active conversations that create performance bottlenecks?

“I started by stating assumptions out loud which felt good, but I underestimated how deep they'd go on fanout.”

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Discord·Product Manager·Onsite - Product Sense / Strategy

May 2026

PM interview at Discord, one question about measuring success for their game purchasing feature. Pretty product-analytics-heavy, no behavioral stuff from what I remember.

How would you measure the success of Discord's new game purchasing feature?

“I went straight to revenue metrics and the interviewer kind of just waited.”

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Discord·Software Engineer·Technical Phone Screen

May 2026

Got a coding question for a Data Engineer role at Discord that was basically a string manipulation problem dressed up with some case-sensitivity nuance. Short and focused, probably a technical screen.

Write a function that takes two strings and returns the words that appear in only one of them, preserving the original casing but treating words as case-insensitive for comparison purposes.

“The case-insensitivity thing is what makes it non-trivial.”

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Discord·Software Engineer·Technical Phone Screen

May 2026

Data Engineer round at Discord, basically a coding question dressed up as a data modeling exercise. You build an in-memory game catalog and then write a few lookup functions over it. Pretty approachable if you're comfortable with dicts and basic iteration.

Given a list of game metadata records (name, release date, platforms, genre, publisher, optional country, Discord servers), design an in-memory data structure to store them and implement lookup functions: get a game's genre by name, get all games by genre, get the games available on the most platforms, and get all games available on exactly N platforms.

“The structure part felt straightforward, just a dict keyed by lowercased name.”

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