Reddit Software Engineer Interview Questions

Does having a name brand company help validate past experiences at unknown companies

I’m looking to understand this from the point of view of experienced devs who have worked initially at non-recognizable firms and then made the switch to recognizable tech or non-tech companies. **Has

reddit software engineer onsite interview experience with ml case study

First Round, ML Case Study 参考 https://www.1point3acres.com/interview/thread/1137582 但是有 missing data, 并且 class imbalance, 20% positive label 最后还有时间做了一点 feature engineering, normalize time spend per person 最后最出来的 F1 score > 0.97 Final Rounds 第一轮 ML Fundamental, 讲怎么build cvr model 第二轮 ML SD, 非常偏重 inference 和 feature serving 第三轮 Coding，Billing Status 第四轮 HM 常规BQ

Word Search II

Word Search II Given a 2-D grid of characters `board` and a list of strings `words`, return all words that are present in the grid. For a word to be present it must be possible to form the word with

Feature Store

Feature Store ## Problem Statement Design a feature store for Reddit's ML platform. Explain how offline and online feature storage stay consistent, how features are computed and materialized, how tr

Dictionary Word Transformation Path

Dictionary Word Transformation Path ## Problem Overview You are given: * a `start` word * a `target` word * a dictionary of allowed words Determine whether the words can be connected by a valid tran

Report Chain

Report Chain ## Problem Overview You are given an org chart as a `list[list[str]]`. Each inner list has the form: ```python [manager, report_1, report_2, ...] ``` For example: ```python [["A", "B",

Tennis Score Game

Tennis Score Game ## Problem Overview Design a two-player game with three core methods: * `add_score(player)` * `get_score()` * `get_result()` The interview then adds a follow-up: convert the score

Design a Gaming Leaderboard Service

Design a Gaming Leaderboard Service Imagine you are building a backend service for game studios. Games run on players' computers, and after a game session ends the client wants to show two things ri

Design Reddit Live Chat

Design Reddit Live Chat Design Reddit Live Chat for large live events such as the Super Bowl. Users join a live discussion tied to a post or event, receive messages in real time, send messages if al

Moderator List Hierarchy

Moderator List Hierarchy ## Problem Overview Implement a Reddit-style moderator list from a newline-delimited log string. The interview usually comes in three parts: 1. A single mod list 2. Multiple

Video Recommendation

Video Recommendation ## Problem Statement Design a video recommendation system for Reddit. Focus on how candidate generation, ranking, serving, and feedback loops work end to end, and how user inter

ML Fundamentals

ML Fundamentals ## Problem Overview This round is a fundamentals-heavy Machine Learning Engineer discussion. The interviewer typically starts with a simple supervised learning setup, then uses a plo

Post Click Prediction

Post Click Prediction ## Problem Overview This Reddit Machine Learning Engineer interview is a practical tabular modeling exercise done in a Jupyter notebook. You are given a clean JSON dataset wher

Merge Chat Message Windows

Merge Chat Message Windows ## Problem Overview You are given an existing API: ```python def get_chat_messages(message_id: int) -> list[Message]: ... ``` For a given `message_id`, it returns the surr

Logger Rate Limiter

Logger Rate Limiter Design a logger system that receives a stream of timestamped messages. A message may be printed only if the same message has not been printed in the last `10` seconds. Implement