Backend Engineer Interview Questions

Showing 1–25 of 25 results

• AirbnbHard·Backend Engineer
  Design a Rental Marketplace Backend

  This problem tests your ability to design a distributed, high-scale rental marketplace platform, focusing on concurrency control for bookings, efficient geo-spatial searching, and data consistency.

  System DesignOnsiteDistributed SystemsConcurrencyGeo-spatial
• AirwallexMedium·Backend Engineer
  Design a Hotel Booking Platform Down to the SQL Tables and Booking Transaction

  Design a hotel booking platform where travelers search by destination and dates and book rooms, down to the SQL tables and the booking transaction. Tests schema design with real constraints, preventing double booking under concurrency, payment holds and expiry, and a search path that scales separately.

  System DesignOther
• CoinbaseMedium·Backend Engineer
  Design a Real-Time Asset Price Service

  Design a high-throughput, low-latency price ingestion and distribution service that normalizes multi-exchange market data, reconciles conflicting ticks, and delivers live prices to internal services and retail clients.

  System DesignOnsiteDistributed SystemsWebSocketsReal-Time Data
• CursorMedium·Backend Engineer
  Design Scalable Notification Rate Limiter

  This question evaluates expertise in designing distributed rate-limiting systems with hierarchical quotas, focusing on concurrency control, exact rolling-window counting, and correctness under concurrent stateless servers; it belongs to the System Design domain and tests practical application of distributed systems, storage, and API design as well as conceptual understanding of atomicity and consistency. It is commonly asked to assess reasoning about atomic decision-making across multiple scopes, scalability and partitioning strategies, handling reconfiguration and operational concerns, and the trade-offs between correctness and system performance (English).

  System DesignTechnical Screen
• DatabricksMedium·Backend Engineer
  Design a Distributed File System

  This question tests the ability to design a scalable, fault-tolerant distributed file system by addressing challenges in metadata management, data chunking, and cluster availability.

  System DesignTechnical ScreenDistributed SystemsStorageScalability
• DatabricksMedium·Backend Engineer
  Design a Distributed File System, Scoping the Requirements Yourself

  Design a distributed file system from a one-line prompt, driving the scoping of workload, semantics, scale and durability yourself. Tests separating metadata from data, block replication and placement, read and write paths, failure recovery, and scaling the namespace for a staff-level backend role.

  System DesignOnsite
• HarveyMedium·Backend Engineer
  Design a secure document vault

  This question evaluates a candidate's competencies in secure backend system design, covering authentication and authorization, metadata and object storage architectures, integrity verification for chunked uploads, scalability, and operational reliability.

  System DesignOnsite
• InstacartMedium·Backend Engineer
  Design Idempotent Due-Date and Hold Notifications

  Design idempotent library notifications for upcoming and current due dates plus FIFO hold availability. Use stable business-event identities, transactional scheduling, atomic recipient claims, state rechecks, retries, reconciliation, and clear frontend distinctions among holds, offers, and checkouts.

  System DesignOnline Assessment
• NRNew RelicMedium·Backend Engineer
  Design a Kafka Consumer Service That Groups Trace Events by Trace ID

  Design a distributed service that consumes trace events from Kafka, groups every event sharing a trace ID, and hands each complete trace to an existing processing function. Covers partitioning, in-memory versus external state, deciding when a trace is complete, and traces that stay open for hours.

  System DesignOnsite
• NuroHard·Backend Engineer
  Design Webhooks and Metric Aggregation

  Design a webhook delivery platform and vehicle telemetry aggregation system. The solution covers multi-tenant subscriptions, at-least-once delivery, retries, signing, DLQs, endpoint isolation, high-volume ingestion, stream processing, raw storage, rollups, alerting, late events, and downsampling.

  System DesignOnsite
• OktaMedium·Backend Engineer
  Design Cross-Domain SSO and OIDC Access to Third-Party Tools

  Design cross-domain SSO with OIDC authorization-code flow, separate site sessions, secure account linking, third-party federation, and delegated API authorization.

  System DesignOnsite
• OktaMedium·Backend Engineer
  Design Single Sign-On Across Two Acquired Sites With OIDC Federation

  Design cross-domain single sign-on after one company acquires a second site on a different domain, then extend it to many sites and to delegated API access for third-party tools, covering the authorization-code flow, session separation, and the authentication-versus-authorization distinction.

  System DesignOnsitesystem-designauthenticationoidc
• OOpendoorMedium·Backend Engineer
  Design Map-Based Home Search

  This problem tests the ability to design a geo-spatial search service capable of handling high-frequency map interactions, filtering, and data consistency at scale.

  System DesignTechnical ScreenGeo-spatialCachingScaling
• OracleMedium·Backend Engineer
  Design a Distributed Rate Limiter

  This problem tests the ability to design a scalable, low-latency distributed system for enforcing traffic quotas across multiple geographic regions with considerations for consistency and burst handling.

  System DesignOnsiteDistributed SystemsRate LimitingScalability
• OracleMedium·Backend Engineer
  Design a High-Volume Healthcare Data Ingestion Pipeline

  This question tests the ability to design a resilient, high-throughput ETL pipeline for sensitive and messy healthcare data, focusing on fault isolation, data integrity, and architectural scalability.

  System DesignOnsiteETLData PipelineScalability
• RipplingMedium·Backend Engineer
  Design a News Aggregator That Builds Personalized Feeds from Publisher APIs

  System design question on building a news aggregator that polls many publisher APIs, stores only article metadata, and serves each user a paginated feed from the publishers and categories they follow. It tests polling schedules and stop conditions, rate-limit and outage handling, feed merging with deduplication, stable cursors, and bounded storage.

  System DesignOnsite
• RobinhoodMedium·Backend Engineer
  Scale Word-Frequency Processing Beyond One Machine

  This question tests the ability to design a distributed data processing pipeline that handles large-scale text files by balancing memory constraints, horizontal scalability, and data integrity.

  System DesignTechnical ScreenDistributed SystemsMapReduceScalability
• RRokuMedium·Backend Engineer
  Design a high-throughput ad exchange

  This problem tests your ability to design a low-latency, high-throughput distributed system capable of managing real-time bidding (RTB) auctions for streaming video advertisements.

  System DesignOnsiteDistributed SystemsLow LatencyHigh Throughput
• SalesforceEasy·Backend Engineer
  Design a Chat Analytics Backend

  This question evaluates a candidate's competence in designing large-scale analytics backends, covering data ingestion, event and metric schemas, near-real-time and historical analytics, metric computation and slicing, data freshness and deduplication, privacy and access control, operational monitoring, and the API/query layer.

  System DesignOnsite
• Scale AIEasy·Backend Engineer
  Design a Durable Task Scheduling Service

  Design a resilient, distributed task scheduling service that decouples scheduling from execution, supporting both delayed one-time tasks and recurring cron jobs with strong durability and at-least-once delivery.

  System DesignOnsiteDistributed SystemsTask SchedulerConcurrency
• SpotifyMedium·Backend Engineer
  Design a Public Upload and Hosting Service for Playlist Cover Images

  A Spotify system design question: design a service that lets users upload, replace and remove a public cover image for their playlists, served to the app and to third-party embeds. Follow-ups cover how an auditor would review image changes and how upload and processing failures are handled.

  System DesignOnsite
• TeslaMedium·Backend Engineer
  Design booking and settlement systems

  This question evaluates backend system design competencies such as concurrency control, transactional integrity, reconciliation, file ingestion and processing, idempotency, API design, and operational reliability.

  System DesignOnsite
• VValonMedium·Backend Engineer
  Design Correct Stateful Services for Irregular Financial Events

  A systems-design interview about correct stateful processing for sparse records, out-of-order loan events, investor payment allocation, and authenticated APIs. It emphasizes idempotency, ledgers, exact arithmetic, recovery, and auditability.

  System DesignOnsite
• ZooxMedium·Backend Engineer
  Design Real-Time Vehicle Location Tracking

  Design a high-throughput, low-latency telemetry ingestion and distribution system that streams autonomous vehicle coordinates to client dashboards and rider apps.

  System DesignTechnical ScreenReal-TimeGeospatialWebSockets
• ZooxHard·Backend Engineer
  Design a Ride-Hailing Platform

  This question tests your ability to design a highly scalable, real-time geo-spatial matching system that handles low-latency requests for vehicle dispatching and location tracking.

  System DesignOnsiteGeo-spatialScalabilityDistributed Systems