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Interview Questions
Practice 9403 coding, system design and machine learning questions from 546 companies, sorted by role, topic and interview round. Every question has step-by-step hints, a code runner that supports 8 languages and an AI mentor; members also get the full solution walkthrough.
- 9403
- Questions
- 546
- Companies
- 11
- Topics
- 8
- Languages
Showing 2941–2970 of 3640 results
- RipplingMediumSoftware EngineerImplement an In-Memory File System
Design and implement an in-memory file system supporting directory creation, file appending, reading, and lexicographically sorted path listings.
Coding & AlgorithmsOnsitetrietreedesign - RipplingMediumMachine Learning EngineerImplement stack and interval algorithms with tests
This question evaluates implementation-level competencies with fundamental data structures and algorithms—stack-based bracket validation, interval merging with open/closed endpoint semantics, and arithmetic expression evaluation using stacks—while also measuring the ability to design comprehensive unit tests; category: Coding & Algorithms for a Machine Learning Engineer role. It is commonly asked to gauge practical coding ability, correctness under tricky edge cases and input semantics, and test-coverage awareness, representing a practical application-level assessment that also requires conceptual reasoning about invariants and boundary behavior.
Coding & AlgorithmsOnsite - RipplingHardSoftware EngineerPresent a Project and Reflect
This question assesses the candidate's ability to articulate the end-to-end lifecycle of a complex project, focusing on technical decision-making, team collaboration, and the ability to critically analyze one's own performance.
Behavioral & LeadershipOnsiteBehavioralLeadershipCommunication - RipplingMediumSoftware EngineerPrevent Duplicate Payments Under High Load
Design a highly reliable payment processing system that guarantees exactly-once execution and prevents duplicate charges during high-concurrency spikes and downstream failure scenarios.
System DesignOnsiteDistributed SystemsPaymentsConcurrency - RipplingMediumBackend EngineerProcess a Task List: Deduplicate, Drop Completed, Sort by Priority, and Nest Subtasks
Senior backend coding question: process a batch of scheduler tasks by removing duplicates on description and due date, dropping completed tasks, sorting by priority, and placing each subtask directly after its parent. It tests clarifying ambiguous policies, orphan and cycle handling, O(n log n) design, and verified use of an AI coding assistant.
Software Engineering FundamentalsOnsite - RipplingMediumBackend EngineerSenior Backend Hiring Manager Deep Dive: Idempotency, SLAs, Changed Decisions, and Pushback
Senior backend hiring manager round covering your proudest project with deep dives on idempotency and SLA definition and monitoring, a technical decision you reversed, a design a colleague challenged, and company-specific motivation. It tests ownership, technical depth, judgment under disagreement, and honest self-reflection.
Behavioral & LeadershipOnsite - RipplingMediumSoftware EngineerStaff Engineer Hiring-Manager Round: Platform Ownership, AI Adoption, and Cross-Team Influence
This question assesses the candidate's ability to drive complex, cross-functional engineering initiatives and their strategic approach to integrating emerging technologies like AI into legacy or established platforms.
Behavioral & LeadershipOnsiteLeadershipSystem ArchitectureStakeholder Management - RipplingMediumSoftware EngineerTrack article votes and last three flips
This question evaluates a developer's ability to design in-memory data structures that support constant-time vote updates, score aggregation, and recent flip-event tracking while handling vote-change semantics.
Coding & AlgorithmsOnsite - RipplingMediumSoftware EngineerWhy do you want to join this company?
This question evaluates a candidate's ability to articulate past experience and measurable impact, communicate clear motivation, and demonstrate fit for a specific team or company, targeting communication, self-presentation, leadership, and career-alignment competencies for a Software Engineer role.
Behavioral & LeadershipOnsite - RobinhoodMediumFrontend EngineerBuild a Weekly Calendar
This question evaluates frontend UI engineering skills, focusing on interactive interface construction, event handling, and state modeling to maintain a single source of truth for events in a weekly calendar grid, and it belongs to the web frontend development and UI/state-management domain.
Coding & AlgorithmsOnsite - RobinhoodMediumSoftware EngineerClarify Friendship Rules and Money-Transfer Semantics Before Choosing an Algorithm
Clarify friendship and money-transfer requirements, separate graph reachability from accounting, and reason about a conditional implementation and invariants.
Software Engineering FundamentalsOnsite - RobinhoodHardSoftware EngineerCount Unique Dependents in a Referral DAG
Count unique direct and transitive dependents in a DAG, preserving edge direction, ignoring unknown endpoints, and handling shared descendants without double-counting.
Coding & AlgorithmsOnsite - RobinhoodMediumData ScientistCreate OHLC Aggregates from Tick Data in Python
This question evaluates a candidate's ability to perform time-series bucketing and OHLC aggregation from tick data, testing skills in data parsing, stateful aggregation, and handling missing-interval forward-filling; it falls under Data Manipulation (SQL/Python) and assesses practical application rather than purely conceptual understanding.
Data Manipulation (SQL/Python)Onsite - RobinhoodMediumSoftware EngineerDefend the Complexity and Scalability of a Project
Prepare a project deep dive that withstands repeated questions about technical difficulty and scalability. Define your ownership, defend a genuine trade-off with evidence, identify current bottlenecks, and propose incremental scaling only when measurable signals justify it.
Behavioral & LeadershipOnsite - RobinhoodMediumSoftware EngineerDefine and Calculate Employee Referral Counts
Implement an algorithm to compute direct and total downstream referral counts for every employee in a directed graph that may contain duplicates, converging paths, and cycles.
Software Engineering FundamentalsOnsiteGraphBFSDFS - RobinhoodMediumSoftware EngineerDesign Payment Processing with Idempotency and Reconciliation
Design a resilient payment processing system that interfaces with third-party payment gateways, guarantees exactly-once execution via idempotency, manages complex payment state machines, and resolves discrepancies via reconciliation.
System DesignOnsitePaymentsIdempotencyDistributed Systems - RobinhoodMediumData ScientistDesign Real-Time Analytics Pipeline with Kafka and Flink
This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Design Real-Time Analytics Pipeline with Kafka and Flink states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipOnsite - RobinhoodMediumSoftware EngineerDesign a Cron Job Scheduler for 100K Jobs With At-Least-Once Execution
A system design question about a cron job scheduler that stores about 100,000 recurring job definitions, runs up to 10,000 jobs at once and guarantees at-least-once execution. It tests data modeling, including whether a schedule belongs on the job, finding and dispatching due jobs at scale, and failure handling with leases and retries.
System DesignOnsite - RobinhoodHardSoftware EngineerDesign a Distributed Scheduler with At-Most-Once Runs
Design a distributed scheduler around strict at-most-once run starts, durable identities, ambiguous crashes, SLA failures, queue recovery, logs, and notification outboxes.
System DesignOnsite - RobinhoodMediumSoftware EngineerDesign a Fault-Tolerant Distributed Job Scheduler
This question tests the ability to design a distributed, fault-tolerant system capable of scheduling and executing tasks reliably at scale, emphasizing durability, state management, and consistency.
System DesignOnsiteDistributed SystemsReliabilityTask Queues - RobinhoodMediumFrontend EngineerDesign a Photo Album App
This question evaluates proficiency in frontend system design, specifically client-side component and data architecture, state management and normalization, real-time synchronization, and large-media upload flows; it sits in the System Design domain with a Frontend Engineer focus and tests practical application of these competencies.
System DesignOnsite - RobinhoodMediumSoftware EngineerDesign a Photo Management Service
This question evaluates a candidate's ability to design scalable, reliable photo management systems, focusing on API design, storage architecture, metadata modeling, album management, and operational concerns for large numbers of users and photos.
System DesignOnsite - RobinhoodMediumSoftware EngineerDesign a Task Scheduler and Executor
Design a high-scale task scheduler for one-time, cron-like, fixed-rate, and fixed-delay execution. Cover versioned task and attempt states, due-time indexing, safe concurrent claims, retries, leases, backpressure, idempotency, recurrence semantics, and recovery.
System DesignOnsite - RobinhoodMediumSoftware EngineerDesign a constrained cache and secure string validator
This question tests the ability to implement a thread-safe, size-constrained cache (LRU-like) and robust string validation logic for identifying malformed or potentially malicious input strings.
Coding & AlgorithmsOnsiteConcurrencyLRUHashing - RobinhoodMediumSoftware EngineerDesign a distributed job scheduler
This question tests the ability to design a fault-tolerant, scalable distributed system capable of scheduling one-time and recurring background tasks with guaranteed execution semantics.
System DesignOnsiteDistributed SystemsScalabilityDatabase Design - RobinhoodMediumSoftware EngineerDesign a live and historical stock quote API fed by a redundant exchange trade feed
A system design question that asks for a stock quote API serving live prices at about 10 million requests per second and one-day, one-month and one-year history at about 1 million, fed by two redundant exchange trade connections. It tests sequence-number arbitration, gap replay, fan-out of live state, bar aggregation and caching at scale.
System DesignOnsite - RobinhoodMediumSoftware EngineerDesign a referral leaderboard with chain-based counts
This question evaluates a candidate's ability to model and compute transitive referral counts using graph-like structures and efficient data structures, testing skills in algorithm design, counting, and sorting within the Coding & Algorithms domain.
Coding & AlgorithmsOnsite - RobinhoodMediumSoftware EngineerDesign an At-Most-Once Job Scheduler
This question tests the ability to design a distributed, fault-tolerant job scheduler that guarantees tasks are executed no more than once, focusing on state management and concurrency control.
System DesignOnsiteDistributed SystemsConcurrencyFault Tolerance - RobinhoodMediumSoftware EngineerDesign an Order Execution System for Market and Limit Orders with Cancellation
A system design question about building the order execution system for a retail brokerage, where users place market and limit orders and can cancel them. It tests order execution flow, order state transitions with partial fills and cancels, failure handling, tracking user balances, and scaling the design to millions of orders.
System DesignOnsite - RobinhoodEasyData ScientistDesign an experiment to launch fractional shares
This question evaluates a candidate's competency in experimentation design, product analytics, statistical power and sample-size calculation, causal inference, and risk identification within a brokerage product context.
Analytics & ExperimentationOnsite
Rippling
Robinhood