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Software Engineering Fundamentals 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
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- 546
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- 11
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- 8
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Showing 91–120 of 448 results
- Capital OneMediumSoftware EngineerPrepaid Travel Card Case Study: Checks, Trade-offs, Buggy Filter
A three-part case study on prepaid travel cards: weigh the trade-offs of issuing them, manually check sample numbers against length, Luhn, and prefix rules, then debug Python filter code whose conditionals let invalid numbers through. Tests product reasoning, careful manual rule-checking, and evidence-driven debugging.
Software Engineering FundamentalsOnsitecase-studyvalidationdebugging - Capital OneMediumSoftware EngineerReason About and Validate Virtual Card Transactions
Implement a policy validation engine for encoded virtual card numbers against incoming transactions, handling rule parsing, Luhn checksum verification, and structured status reporting.
Software Engineering FundamentalsOnsiteStringsValidationClean Code - Capital OneMediumSoftware EngineerVirtual Card Case Study: Trade-offs, Card Number Rule Checks, and Debugging a Filter
A three-part virtual credit card case study: weigh the benefits and costs of giving merchants virtual card numbers, check five sample numbers against length, Luhn checksum and prefix rules, and debug a Python filter whose conditionals accept invalid numbers. It tests product reasoning, careful manual analysis and evidence-driven debugging.
Software Engineering FundamentalsOnsite - Charta HealthMediumSoftware EngineerDesign a Prefix-Suggestion Search Interface
Design and implement an in-memory prefix suggestion engine that indexes document titles, provides ranked auto-complete results, and prevents out-of-order race conditions from asynchronous search queries.
Software Engineering FundamentalsOnsiteTrieSearchConcurrency - Chicago Trading CompanyMediumSoftware EngineerTrace Virtual Address Translation Through TLBs, Page Tables, and Caches
This question tests the understanding of memory hierarchy and virtual memory translation, specifically the interactions between TLBs, page tables, and hardware caches.
Software Engineering FundamentalsOnsiteVirtual MemoryPagingMMU - CiscoEasySoftware EngineerDoes a Successful Ping Mean Port 443 Is Reachable? Diagnosing Server Connectivity
A networking fundamentals question asking whether a successful ping to a server proves that port 443 on it is accessible, and how to check the port directly. It tests the difference between ICMP and TCP, the role of firewalls and listening services, and practical connectivity troubleshooting with command-line tools.
Software Engineering FundamentalsOnsite - CiscoEasySoftware EngineerExplain BGP: Sessions, Route Exchange, and Best-Path Selection
A networking fundamentals question asking the candidate to explain the Border Gateway Protocol: why it exists, how peers form sessions and exchange routes, how a router selects the best path, and how BGP differs from interior protocols such as OSPF. It also probes troubleshooting and testing.
Software Engineering FundamentalsOnsite - CiscoEasySoftware EngineerImplement a Python To-Do Task Manager Class with CRUD and Status Rules
A Python coding question asking for a to-do task manager class with create, read, update, and delete operations, where every task has a status of new, pending, or resolved. It tests data modeling, input validation, status transition rules, error handling for missing tasks, and testable class design.
Software Engineering FundamentalsOnsite - CiscoEasySoftware EngineerPython Multiple Inheritance: Which Parent Method Runs When Names Collide
A Python fundamentals question about multiple inheritance in which two parent classes define a method with the same name and a child class inherits from both. It tests the method resolution order, C3 linearization, how super() follows that order, and when composition is the better design.
Software Engineering FundamentalsOnsite - CiscoEasySoftware EngineerPython and pytest Fundamentals: Fixtures, Decorators, and Generators
A three-part Python and pytest fundamentals question covering how fixtures are injected, scoped, torn down, and shared; how decorators work and how to write one that preserves metadata; and how generators produce values lazily. It tests core language mechanics used in test automation.
Software Engineering FundamentalsOnsite - CiscoEasySoftware EngineerTesting a New Feature: Planning Test Cases and Handling Flaky Tests
A two-part QA question on how to test a new feature and plan its test cases, and how to find, diagnose, and prevent flaky automated tests. It evaluates requirement analysis, test design techniques, risk-based prioritization, test levels, release exit criteria, and keeping a test suite trustworthy.
Software Engineering FundamentalsOnsite - Citadel SecuritiesMediumSoftware EngineerDetect Currency Arbitrage and Return a Profitable Conversion Cycle
Given a list of currency conversion rates, determine whether an arbitrage opportunity exists and return a sequence of conversions that ends in the starting currency with more money than it began with. Tests graph modeling, cycle detection, reconstruction of the profitable sequence, and handling of floating-point precision.
Software Engineering FundamentalsOnsite - Citadel SecuritiesMediumSoftware EngineerThread-Safe Producer-Consumer Queue: Mutex, Then Spin Lock, Then Lock-Free
Implement a thread-safe producer-consumer queue in C++, first with a mutex, then with a spin lock, then as a lock-free design with explicit memory ordering. Tests the C++ memory model, contention and cache effects, blocking versus spinning, and where memory is allocated on the hot path.
Software Engineering FundamentalsOnsite - CohereMediumFrontend EngineerBuild a Credit Card Form With Validation and Linked Input Fields
A front-end UI coding question: build a credit card form with card number, name, expiry and security code, where every field is validated and the fields are linked, so the detected card network changes formatting and security-code rules. It tests state design, caret-safe input formatting, error timing, accessibility and safe handling of card data.
Software Engineering FundamentalsOnsite - CohereMediumMachine Learning EngineerBuild an LLM-driven text-game agent
This question tests the ability to design a robust pipeline for an LLM-based agent interacting with a stateful environment, focusing on context management, output validation, and error recovery.
Software Engineering FundamentalsOnsiteLLMPrompt EngineeringSystem Design - CohereMediumMachine Learning EngineerReplace a Heuristic Terminal Text Game's Python Logic With LLM Calls
A live coding round: replace the heuristic Python implementation of a terminal text game with one driven by an LLM while keeping the game playable end to end. AI assistants are allowed, but the round judges your own implementation and debugging, including validating model output, fallbacks, and tests with a fake model.
Software Engineering FundamentalsOnsite - CoinbaseHardSoftware EngineerDebug and Extend Cursor Queries
This question evaluates understanding of iterator/cursor semantics, stateful side effects and mutation, practical debugging and trace reasoning, and basic query API design such as adding limit or order_by features.
Software Engineering FundamentalsOnsite - CoinbaseMediumBackend EngineerEvolve 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 - CoinbaseHardFrontend EngineerImplement a Reusable Dropdown Component
This question evaluates skills in reusable frontend component design, including API design, state management (controlled vs uncontrolled), event handling, keyboard navigation, and accessibility (roles, focus behavior, and ARIA) for production-ready UI components.
Software Engineering FundamentalsOnsite - ConfluentMediumSoftware EngineerDesign an LRU Cache with a Constant-Time Average
Design a fixed-capacity LRU cache whose get, put, and current-value average operations all run in expected constant time. Reason through map and recency-list invariants, running-sum updates, replacement and eviction edge cases, numeric precision, overflow, and tests that catch aggregate or ordering bugs.
Software Engineering FundamentalsOnsite - ConfluentMediumSoftware EngineerDocument Search: Exact Word Match, Non-Adjacent Phrase Match and AND/OR Queries
A progressive coding round that builds search over a collection of documents. It starts with exact whole-word lookup, extends to multi-word queries whose words need not be adjacent, and ends with words combined by AND and OR, testing inverted indexes, set operations and clarifying ambiguous query semantics.
Software Engineering FundamentalsOnsite - ConfluentMediumSoftware EngineerExplain Linux Command Execution, Filesystems, and Isolation
Explain what Linux does from shell parsing through process creation, exec, waiting, and exit status, then trace paths, permissions, file descriptors, directories, procfs, and network inspection. Compare containers and virtual machines through their actual isolation boundaries and operational trade-offs.
Software Engineering FundamentalsOnsite - ConfluentMediumSoftware EngineerImplement tail -n for a Very Large File
Implement the core of tail -n for a seekable file that may be many gigabytes without scanning it all when the requested suffix is small. Work through backward block reads, chunk boundaries, trailing-newline semantics, bounded memory, binary-versus-text handling, safe decoding, and mutation assumptions.
Software Engineering FundamentalsOnsite - ConfluentMediumSoftware EngineerMachine Coding: Word Search and Ordered Phrase Search Across a List of Documents
A machine-coding exercise that asks you to build a search component over a list of text documents, first finding the documents that contain a given word and then those where a phrase's words appear in the same sequence. It tests tokenization choices, index design, and handling of repeated words and edge cases.
Software Engineering FundamentalsOnsite - ConfluentMediumSoftware EngineerPick Budget Line Items That Net to an Exact Target
A staged algorithm discussion: decide whether some subset of budget line items nets to an exact target amount, first with only charges and then with refunds (negative amounts) mixed in, then produce one such subset, then every distinct subset, reasoning about dynamic programming, pruned backtracking, and why negative values change the problem.
Software Engineering FundamentalsOnsitedynamic-programmingbacktrackingsubset-sum - ConfluentMediumSoftware EngineerPick Numbers Summing to a Target: Existence With Negatives, One and All Solutions
A staged coding discussion about choosing integers from a list so that they add up to a target. It asks whether a solution exists with only positive numbers and then with mixed signs, for one solution and for every solution without duplicates, and for optimizations, testing dynamic programming, pruned backtracking and reasoning about negative numbers.
Software Engineering FundamentalsOnsite - ConfluentMediumSoftware EngineerSearch Words and Phrases in a Large Line-Oriented File
Design word and exact-phrase search over a line-oriented file that may be much larger than memory. Compare a streaming one-off scan with a persistent positional inverted index, defining tokenization, Unicode and punctuation behavior, file-version binding, updates, result locations, and resource trade-offs.
Software Engineering FundamentalsOnsite - CoreweaveMediumSoftware EngineerBuild an OAuth-based data migration client
This question evaluates proficiency in OAuth 2.0 client-credentials authentication, API integration and pagination, JSON data transformation and checksum-based data integrity, token lifecycle management, retries, and idempotency within the Software Engineering Fundamentals category.
Software Engineering FundamentalsOnsite - CoreweaveMediumSoftware EngineerDesign Tree Operations with DFS and BFS
Implement and compare Breadth-First Search (BFS) and Depth-First Search (DFS) operations on an N-ary tree representing a hierarchical compute cluster.
Software Engineering FundamentalsOnsiteTreesBFSDFS - CoreweaveMediumSoftware EngineerRepresent and Evaluate Boolean Predicate Expressions
Design an object-oriented or tree-based representation for boolean predicate expressions and implement an evaluation engine that supports logical operators, comparison operations, and short-circuit evaluation against attribute dictionaries.
Software Engineering FundamentalsOnsiteobject-oriented-designtreesrecursion
Capital One
Citadel Securities
Cohere
Coinbase
Confluent
Coreweave