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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 7201–7230 of 9403 results
- RemitlyHardSoftware EngineerWhiteboard and Deep Dive a Past Project
This question evaluates a candidate's end-to-end system design skills, including architecture decomposition, trade-off analysis, data consistency choices, scalability and resiliency patterns, and integration of operational practices for a user-facing distributed service.
System DesignOnsite - RenderMediumSoftware EngineerCount Blocked Rate-Limited Requests
This question evaluates understanding of rate-limiting logic, sliding-window time-based counting, and data structure design for tracking per-IP and per-(IP, host) request histories.
Coding & AlgorithmsTechnical Screen - RenderMediumSoftware EngineerFind the Five Busiest Client IPs in Request Logs
Aggregate completed HTTP request logs across files to find the top five client IPv4 addresses, excluding auxiliary messages and applying deterministic count ties.
Coding & AlgorithmsTechnical Screen - RenderMediumSoftware EngineerRate Limit an API During a Traffic Attack
Design API rate limiting with token buckets, layered identities, endpoint costs, distributed-state tradeoffs, and measurable protection of legitimate traffic.
System DesignTechnical Screen - ReplitMediumSoftware EngineerDesign a Multi-Channel Notification System
Design a resilient, multi-channel notification service that routes notifications across in-app, email, SMS, and push channels while honoring user preferences, idempotency, rate limits, and provider status tracking.
System DesignOnsiteDistributed SystemsMessage QueuesAPI Design - Resolve.AiMediumSoftware EngineerDesign a Weighted Log Distributor
This question tests your ability to design a distributed system that routes incoming log streams to multiple storage clusters based on specified weight configurations while ensuring high availability and fault tolerance.
System DesignOnline AssessmentLoad BalancingDistributed SystemsData Pipelines - Retell AIMediumSoftware EngineerConnect a Local FastAPI Service to an AI Agent Platform to Save and Read Back Issues
A live coding exercise on connecting a local Python FastAPI service to a hosted conversational AI agent platform so the agent can save issues a user reports and read past issues back during a conversation. It tests tool and endpoint design, making a local server reachable, user identification, speech-friendly responses and failure handling.
Software Engineering FundamentalsTechnical Screen - Retell AIEasySoftware EngineerDescribe a Time You Explained a Complex Technical Concept to Non-Technical People
A behavioral question for a customer-facing engineering role: describe one specific time you explained a complex technical concept to a non-technical audience and how you approached it. Tests STAR storytelling, audience analysis, accurate analogies and how the candidate checks that the message landed.
Behavioral & LeadershipHR Screen - Retell AIHardSoftware EngineerDesign a Cloud Call-Center Platform for Programmatic Outbound Calls
This question evaluates a candidate's ability to design a distributed, asynchronous system under hard external rate and capacity constraints. It tests system design fundamentals such as queueing, backpressure, state-machine modeling, and multi-tenant fairness, commonly asked to assess architectural reasoning at a practical, applied level rather than pure theory.
System DesignTechnical Screen - Retell AIMediumSoftware EngineerDesign a Smooth Per-Customer Calls-Per-Second Controller
Design a distributed outbound call pacing service that enforces smooth per-tenant calls-per-second (CPS) rate limits while ensuring durable queueing, priority scheduling, and safe failover.
System DesignTechnical ScreenRate LimitingDistributed SystemsTask Scheduling - Retell AIHardSoftware EngineerDesign and Implement a Mini SQL Query Engine
This question evaluates a candidate's ability to design and build a small SQL query engine, covering tokenization, parsing, and query execution over in-memory tables. It tests system design and compiler-style thinking, including how to scope a large problem into an extensible v1 and reason about extending it with sorting, aggregation, and joins. This is a system design and practical implementation question assessing both architectural judgment and coding ability.
System DesignTechnical Screen - Retell AIMediumSoftware EngineerDesign collaborative document editing backend
This question evaluates a candidate's ability to design real-time collaborative systems, focusing on distributed systems concepts, concurrency control, consistency models, synchronization, and scalable backend architecture.
System DesignOnsite - Retell AIEasySoftware EngineerEvaluate a Small Stack-Based Integer Language
Implement an interpreter for a stack-based integer language supporting arithmetic, stack manipulation, output, and immediate error reporting with partial output preservation.
Coding & AlgorithmsTechnical Screenstackparsingsimulation - Retell AIMediumSoftware EngineerQuery an Indexed In-Memory Numeric Table
This problem tests the ability to implement efficient multi-column indexing using binary search and sorted set intersections to handle complex range queries.
Coding & AlgorithmsTechnical ScreenData StructuresBinary SearchIndexing - RetoolMediumSoftware EngineerCompute max profit with forced trades
Compute max profit with forced trades evaluates algorithm design, data structures, correctness, complexity, edge cases, and implementation details in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Coding & AlgorithmsTechnical Screen - RetoolHardSoftware EngineerDesign car rental schema and APIs
This question evaluates data modeling, transactional integrity, concurrency control, REST API and workflow design, and system scalability within the car rental domain in the System Design category.
System DesignTechnical Screen - ReutersEasySoftware EngineerDiscuss overfitting, contrastive learning, transformers
This question evaluates understanding of supervised learning generalization (overfitting and underfitting), contrastive representation learning and contrastive loss functions, and transformer architectures, assessing core competencies in model evaluation, representation learning, and neural architecture concepts within the Machine Learning domain.
Machine LearningTechnical Screen - RevolutMediumSoftware EngineerBuild a Java restaurant table booking service that prevents double bookings
A live Java coding exercise to build a restaurant table booking system while an AI assistant is allowed. It tests domain modeling, correct interval overlap logic for tables, a clear table allocation policy, thread safety, and how the candidate tests and stays in control of generated code under time pressure.
Software Engineering FundamentalsOther - RevolutHardData AnalystDefine Ultra success and detect suspicious transactions
This question evaluates a candidate's skills in product analytics, cohort and retention measurement, SQL-based metric design and segmentation, and rule-based fraud detection using transactional and activity data.
Analytics & ExperimentationTechnical Screen - RevolutEasyData ScientistDefine Ultra success metrics and detect suspicious transactions
This question evaluates a data scientist's ability to define primary, diagnostic, and guardrail metrics for a product launch and to design rule-based suspicious-transaction detection using available schema, emphasizing metric definition, defensible proxy selection, SQL-based data modeling, and financial-crime domain knowledge.
Analytics & ExperimentationTechnical Screen - RevolutMediumSoftware EngineerDesign automatic travel insurance enrollment triggered by customer location
A system design exercise for a banking app that automatically enrolls opted-in customers in travel insurance when location signals show they are abroad. It tests requirements scoping, an event-driven pipeline, idempotent enrollment with an insurer, data modeling, scaling reads and writes, and failure handling.
System DesignOther - RevolutMediumSoftware EngineerDesign multi-region banking data synchronization
This question evaluates competency in distributed systems and data consistency for financial applications, emphasizing replication, transaction correctness, conflict resolution, idempotency, and operational resilience.
System DesignTechnical Screen - RevolutMediumSoftware EngineerExplain DB concurrency, debugging slowness, DDD and CQRS
This question evaluates understanding of database concurrency control and isolation anomalies, backend performance investigation and diagnostic skills, and knowledge of architectural concepts DDD and CQRS, testing competencies in transaction semantics, operational troubleshooting signals, and architectural trade-offs.
Software Engineering FundamentalsTechnical Screen - RevolutMediumSoftware EngineerImplement a random fixed-size load balancer
This question evaluates understanding of randomized selection, efficient in-memory data structures, and API/state management for a fixed-capacity load balancer that must support addNode, removeNode, and uniform random routing while handling duplicates, removals, and empty-state behavior.
Coding & AlgorithmsTechnical Screen - RevolutMediumSoftware EngineerImplement a thread-safe money transfer
This question evaluates a candidate's mastery of concurrent programming and data-integrity principles, focusing on thread safety, atomic state updates, and deadlock avoidance when transferring funds between shared accounts.
Coding & AlgorithmsTechnical Screen - RilletMediumBackend EngineerDistribute Annual Revenue Across Twelve Months
This problem tests logic, integer arithmetic, and edge-case handling by requiring the distribution of a total sum into equal parts while managing remainders without using floating-point numbers.
Coding & AlgorithmsTechnical ScreenAlgorithmsInteger ArithmeticData Manipulation - RiotgamesEasySoftware EngineerAdmit and Recover from a Public Mistake
This question assesses the candidate's professional integrity, emotional intelligence, and ability to prioritize organizational impact over personal ego when a technical error occurs.
Behavioral & LeadershipTechnical ScreenOwnershipCommunicationCrisis Management - RiotgamesEasySoftware EngineerAggregate Letter-Number Groups
This problem tests string parsing, data aggregation using a hash map, and sorting techniques.
Coding & AlgorithmsTechnical ScreenStringsHash MapsSorting - RiotgamesEasySoftware EngineerChoose Between For and While Loops
This question evaluates your conceptual understanding of control flow structures, specifically focusing on readability, maintainability, and error prevention in loop selection.
Software Engineering FundamentalsTechnical ScreenControl FlowBest PracticesCode Quality - RiotgamesEasySoftware EngineerDescribe a Difficult Project
This question assesses the candidate's ability to navigate complex technical challenges, demonstrate ownership, and communicate their decision-making process within a team environment.
Behavioral & LeadershipTechnical ScreenBehavioralLeadershipCommunication
Remitly
Retell AI
Revolut