Backend Engineer Interview Questions

Showing 1–15 of 15 results

• ArmMedium·Backend Engineer
  Explain timing and testability concepts

  This question evaluates a candidate's understanding of digital timing and testability concepts—specifically setup and hold timing, clock skew impacts, mitigation of setup/hold violations, and test methodologies such as scan, DFT and MBIST—within backend digital implementation contexts.

  Software Engineering FundamentalsOnsite
• CoinbaseMedium·Backend Engineer
  Evolve Cursor Pagination Without Breaking Clients

  This problem tests the ability to design stable, deterministic cursor-based pagination systems that handle non-unique sort keys and schema evolution without breaking backward compatibility.

  Software Engineering FundamentalsOnsiteAPI DesignPaginationSQL
• HarveyMedium·Backend Engineer
  Explain project decisions and trade-offs

  This question evaluates proficiency in technical decision-making, trade-off analysis, and system design ownership for backend projects, including architecture rationale, technology selection, and the candidate's specific role and measurable impact.

  Software Engineering FundamentalsOnsite
• LLatitudeaiMedium·Backend Engineer
  Design a Thread-Safe Bounded Blocking Queue

  Tests your ability to design a concurrent, thread-safe bounded blocking queue using synchronization primitives, handle edge cases like spurious wakeups and timeouts, and cleanly coordinate shutdown across multiple threads.

  Software Engineering FundamentalsOnsiteConcurrencyMultithreadingQueue
• LLegoraMedium·Backend Engineer
  Design a Cloud-Agnostic Upload Adapter

  Design a provider-neutral object storage upload client that unifies cloud SDK behaviors while supporting streaming, multipart uploads, error normalization, and provider-specific escape hatches.

  Software Engineering FundamentalsOnsiteapi-designcloud-storageobject-oriented-design
• MintlifyMedium·Backend Engineer
  Design a CRUD API for a document service

  Design the create, read, update and delete API for a document service, covering the resource model, endpoints, request shapes and status codes. It tests REST fundamentals plus production concerns such as concurrent edits, idempotent retries, pagination, authorization, deletion semantics and API versioning.

  Software Engineering FundamentalsOnsite
• MintlifyMedium·Backend Engineer
  Should you add an index for a slow query on a large table's unindexed columns?

  A query on a large database table is slow and the columns it filters on have no index: should you add one? It tests reading query plans, weighing selectivity and query frequency against write cost, designing composite or partial indexes, and building an index safely on a busy production table.

  Software Engineering FundamentalsOnsite
• OktaMedium·Backend Engineer
  Build and Review a Configurable Node.js Token-Bucket Rate Limiter

  Implement a configurable Node.js Express token-bucket rate limiter with monotonic refill, HTTP 429 responses, code-review reasoning, and multi-instance limits.

  Software Engineering FundamentalsOnsite
• OktaMedium·Backend Engineer
  Repair an Express Authentication Endpoint Without Blocking the Event Loop

  Repair an Express authentication endpoint with input validation, asynchronous bcrypt, safe errors, correct HTTP status codes, and event-loop-aware resource controls.

  Software Engineering FundamentalsOnsite
• RipplingMedium·Backend Engineer
  Process 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
• RRokuMedium·Backend Engineer
  Explain concurrency and distributed fundamentals

  This question tests fundamental knowledge of thread-safe collections in Java and core distributed systems architectural patterns, specifically partitioning strategies.

  Software Engineering FundamentalsOnsiteJavaConcurrencyDistributed Systems
• Scale AIEasy·Backend Engineer
  Build a CSV-to-JSON Classification Service

  Implement a resilient data pipeline service that parses CSV records, enriches them using an external classification client with validation and retries, and writes ordered, structured JSON Lines output safely.

  Software Engineering FundamentalsOnsiteData PipelinesConcurrencyError Handling
• SpotifyMedium·Backend Engineer
  On-Call Case Study: Debugging a Misbehaving Production Server

  A Spotify on-call case study: as the engineer paged about a misbehaving production server, investigate by asking for metrics, logs and command output. It tests triage, impact assessment, systematic host and service diagnostics, mitigation trade-offs and incident follow-through.

  Software Engineering FundamentalsOnsite
• SpotifyMedium·Backend Engineer
  Visit-Pattern Counter: Multi-Input Runtime Analysis and Production Hardening

  A Spotify backend coding follow-up: for a function that finds the three-website visit pattern followed by the most distinct users, analyze time and memory using separate input dimensions such as records, users, longest per-user history and distinct sites. It also asks which functional and style changes the code needs before it ships in production.

  Software Engineering FundamentalsOnsite
• TeslaMedium·Backend Engineer
  Explain reliability and runtime fundamentals

  This question evaluates understanding of reliability and runtime fundamentals in backend engineering, covering competencies such as fault tolerance, end-to-end request lifecycles, API gateway degradation, storage engine selection for search, and the distinction between compilers and interpreters.

  Software Engineering FundamentalsOnsite