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Software Engineer 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
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- 11
- Topics
- 8
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Showing 1801–1830 of 5874 results
- DatadogMediumSoftware EngineerDeep-dive a recent project
This question evaluates project ownership, technical leadership, system architecture, trade-off reasoning, and the ability to articulate goals, constraints, decisions, metrics and postmortem lessons in a software engineering context.
Behavioral & LeadershipTechnical Screen - DatadogMediumSoftware EngineerDescribe handling conciseness feedback
This question evaluates a candidate's ability to accept and act on conciseness feedback, encompassing communication clarity, adaptability, measurement of improvement, and leadership influence on stakeholder interactions.
Behavioral & LeadershipTechnical Screen - DatadogMediumSoftware EngineerDesign an LLM Agent System That Automatically Resolves Jira Tickets and Opens Pull Requests
Design an autonomous agent pipeline that ingests Jira bug reports, grounds itself in a multi-repo codebase via code search and retrieval, iterates on a fix in a sandboxed runtime, and opens a validated pull request.
ML System DesignTechnical ScreenLLM AgentsCode GenerationRAG - DatadogHardSoftware EngineerDesign an image detection system
This question evaluates a candidate's competence in designing scalable, reliable end-to-end machine learning systems for image object detection, including ingestion, preprocessing, model serving, data and version management, monitoring, and operational concerns.
ML System DesignTechnical Screen - DatadogHardSoftware EngineerDesign log-query stream processor
Design log-query stream processor evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
System DesignTechnical Screen - DatadogEasySoftware EngineerEngineering Manager Interview: Your Technical Contribution and an Annoying Teammate
A hiring manager conversation for an engineering manager role: introduce yourself, explain your own technical contribution to a project you led, and describe a time a team member annoyed you. It tests whether a manager can separate personal technical judgment from team output and handle interpersonal friction with candor.
Behavioral & LeadershipOnsite - DatadogMediumSoftware EngineerExplain a project concisely and deeply
This question evaluates project leadership, technical ownership, stakeholder communication, decision‑making under trade‑offs, and the ability to quantify measurable impact through a concise overview followed by a deep dive.
Behavioral & LeadershipTechnical Screen - DatadogMediumSoftware EngineerImplement DeleteTree With Limited Filesystem APIs
Implement a robust recursive tree-deletion algorithm using a restricted set of filesystem primitives. This question tests post-order traversal, managing call-stack and heap memory across deep and wide directory structures, and handling edge cases cleanly.
Software Engineering FundamentalsTechnical Screentreestackdfs - DatadogHardSoftware EngineerImplement Prefix Match Filter
This question evaluates understanding of prefix-based string matching, data structure design (hash-based sets and trie/prefix tree), and algorithmic competencies including efficient in-memory storage and deduplication of matches.
Coding & AlgorithmsOnsite - DatadogMediumSoftware EngineerImplement a Snowflake Query Client
This question evaluates API client design, asynchronous query lifecycle management, result retrieval, robust error handling, and secure credential handling for a cloud data warehouse.
Coding & AlgorithmsOnsite - DatadogEasySoftware EngineerImplement buffered file writer with concurrency support
This question evaluates a candidate's ability to implement buffered I/O and design concurrency-safe APIs, exercising skills in data buffering, performance optimization, and thread-safety.
Coding & AlgorithmsTechnical Screen - DatadogMediumSoftware EngineerImplement log storage and querying
This question evaluates a candidate's skill in designing and analyzing log storage and query systems, covering data layout, indexing strategies, time-range scans with optional filters, and time/space complexity reasoning.
Coding & AlgorithmsTechnical Screen - DatadogMediumSoftware EngineerImplement write with internal buffer
This question evaluates proficiency with buffered I/O, buffer management, memory handling, and performance optimization, including maintaining byte order, handling partial writes, and edge cases across consecutive write/flush/close operations.
Coding & AlgorithmsTechnical Screen - DatadogMediumSoftware EngineerMatch logs to prior queries
This question evaluates understanding of streaming algorithms, string indexing, and set-based matching, focusing on designing efficient online data structures to match stored queries against incoming logs within the Coding & Algorithms domain.
Coding & AlgorithmsTechnical Screen - DatologyaiHardSoftware EngineerCursor-Based Text Editor: Typing, Backspace, and Four-Way Cursor Movement
Implement a TextEditor class with a single cursor that supports typing a character, backspace, and rendering the text with a | at the cursor, then extend it with left/right and up/down cursor movement. Tests choice of representation, per-operation cost, and boundary handling across lines of different lengths.
Software Engineering FundamentalsTechnical Screen - DatologyaiEasySoftware EngineerText Editor with a Cursor: Typing, Backspace, and Four-Way Cursor Movement
Implement a text editor class that types characters at a cursor, deletes with backspace, and renders the text with a bar marking the cursor. Follow-ups add left/right and then up/down cursor movement, testing the choice of data structure for cheap edits, boundary handling, and line-aware navigation.
Software Engineering FundamentalsTechnical Screen - DatologyaiEasySoftware EngineerWord Count and Multiset Intersect Using Only a Mock Spark RDD API
Given a minimal mock of a Spark RDD with only flatMap, groupByKey, union and collect, implement a word count function and a duplicate-preserving intersect of two RDDs. Tests composing transformations without map or reduce, tracking which input an item came from, and reasoning about the cost of grouping.
Software Engineering FundamentalsTechnical Screen - DavidaiMediumSoftware EngineerDesign a Scalable Audio AI Processing Platform
Tests the candidate's ability to design a resilient, distributed ML platform for audio processing that supports both interactive and batch workloads, efficient GPU scheduling, and granular failure recovery.
ML System DesignTechnical Screenml-system-designdistributed-systemsgpu-scheduling - Deca TechnologiesMediumSoftware EngineerExplain why you want this company and leadership
This question evaluates motivation and role fit, ownership and execution, leadership experience, and cross-site collaboration by asking for reasons for joining and concrete examples of leading projects.
Behavioral & LeadershipTechnical Screen - DecagonHardSoftware EngineerAdd Nested Begin, Commit, and Abort Semantics to a Shopping Cart
Design and implement an in-memory shopping cart that supports nested transactions via begin, commit, and abort operations with proper scope isolation.
Software Engineering FundamentalsTechnical ScreenTransactionsData StructuresDesign Patterns - DecagonMediumSoftware EngineerCompute exclusive CPU time from nested logs
This question evaluates the ability to interpret execution logs and compute exclusive CPU time, testing skills in parsing structured logs, reasoning about nested execution intervals, and precise time accounting.
Coding & AlgorithmsTechnical Screen - DecagonHardSoftware EngineerCount Legal Tic-Tac-Toe Games from the Empty Board
Implement an exhaustive search algorithm to count all distinct legal game sequences in 3x3 Tic-Tac-Toe, categorized by outcome.
Coding & AlgorithmsTechnical ScreenBacktrackingDFSGame Theory - DecagonMediumSoftware EngineerDeliver Messages in Fixed Batches with Per-Message Retry Delays
Send a list of outbound messages to a provider that only accepts five per call, then retry failed messages only after the provider's own per-message cooldown has elapsed. Tests chunking, scheduling retries by readiness time instead of busy-waiting, and handling partial batch failures cleanly.
Software Engineering FundamentalsTechnical Screenschedulingretriesqueues - DecagonHardSoftware EngineerDesign a Durable Delayed Task Scheduler
Design a distributed, durable task scheduler capable of scheduling millions of tasks to execute at exact future timestamps with high precision, at-least-once delivery, and automatic fault recovery.
System DesignTechnical Screensystem-designdistributed-systemstask-scheduler - DecagonMediumSoftware EngineerDesign a Real-Time AI Voice System
This problem evaluates your ability to design a low-latency, real-time conversational AI system, focusing on component orchestration and performance trade-offs in speech processing pipelines.
ML System DesignTechnical ScreenSystem DesignReal-time SystemsStreaming - DecagonMediumSoftware EngineerDesign a Single-Domain Chatbot
This question evaluates a candidate's ability to design production-grade conversational AI systems, testing competencies in retrieval-augmented generation, document ingestion and indexing, multi-turn session management, prompt construction, model serving, grounding and citation, safety, access control, monitoring, and operational trade-offs.
ML System DesignOnsite - DecagonHardSoftware EngineerDesign a Space-Efficient Versioned Recipe Shopping Cart
Design an in-memory versioned shopping cart that aggregates recipe ingredients for bulk discounts, supports atomic mutations, and allows rolling back and checking out earlier cart snapshots efficiently.
Software Engineering FundamentalsTechnical Screendata-structuresdesignevent-sourcing - DecagonMediumSoftware EngineerDesign a Tic-Tac-Toe Engine
This problem tests your ability to design a state-tracking system for an n x n Tic-Tac-Toe board that allows for constant-time move validation and win detection.
Coding & AlgorithmsTechnical ScreenAlgorithmsData StructuresDesign - DecagonMediumSoftware EngineerDesign an AI Gateway
Design a high-throughput, multi-tenant AI Gateway that provides a unified API, intelligent routing, token-aware rate limiting, and observability across multiple upstream LLM providers.
System DesignTechnical ScreenAPI GatewayLLM InfrastructureRate Limiting - DecagonEasySoftware EngineerDesign rolling-window conversation score tracker
Design a rolling-window tracker for streaming conversation scores that supports score updates, rolling average calculation, and maximum score queries.
Coding & AlgorithmsTechnical ScreenSliding WindowDesignQueue
Datadog
Decagon