25 Must-Do System Design Problems for Tech Interviews

A curated collection of system design problems frequently asked in interviews at top tech companies.

Table of System Design Interview Problems

This table presents 25 essential system design problems that are frequently asked in technical interviews at top technology companies. Each problem is categorized by complexity level (Low, Medium, High) and includes information about which companies commonly ask these questions and for which engineering roles.

#	Problem	Complexity	Companies	Roles	Resources
1	Design a URL Shortening Service (like Bit.ly)	Medium	Google, Amazon, Microsoft, Uber	SWE, SDE, Backend	System Design Primer, Grokking
2	Design Twitter	High	Twitter, Meta, Google, Microsoft	SWE, SDE, Full-stack	System Design Primer, High Scalability
3	Design a Rate Limiter	Medium	Stripe, Cloudflare, Google, Amazon	SDE, SRE, Backend	Stripe Engineering Blog, Grokking
4	Design Netflix or YouTube (Video Streaming Service)	High	Netflix, YouTube, Amazon, Meta	SWE, Media, Backend	Netflix Tech Blog, System Design Primer
5	Design an Online Chat System (like WhatsApp)	Medium	Meta, Signal, Snap, Microsoft	SWE, Backend, Mobile	WhatsApp Architecture, Grokking
6	Design Uber or Lyft	High	Uber, Lyft, DoorDash, Instacart	SWE, Backend, Mobile	Uber Engineering Blog, Grokking
7	Design a Web Crawler	Medium	Google, Microsoft, Amazon, ByteDance	SWE, Search, Data	Google Research, System Design Primer
8	Design Dropbox / Google Drive	High	Dropbox, Google, Microsoft, Box	SWE, Storage, Cloud	Dropbox Tech Blog, System Design Primer
9	Design a Distributed Key-Value Store	High	Amazon, Google, Redis Labs, MongoDB	SWE, Database, Cloud	DynamoDB Paper, Google Spanner
10	Design Instagram	Medium	Meta, Snap, ByteDance, Pinterest	SWE, Full-stack, Mobile	Instagram Engineering, System Design Primer
11	Design a Payment System	High	Stripe, PayPal, Square, Rippling	SWE, Financial, Security	Stripe Engineering Blog, Grokking
12	Design a Search Autocomplete System	Medium	Google, Microsoft, Amazon, LinkedIn	SWE, Search, UX	System Design Primer, Grokking
13	Design a Recommendation System	High	Netflix, Amazon, Spotify, TikTok	SWE, ML, Data	Netflix Recommendation, Amazon ML Blog
14	Design an API Rate Limiter	Medium	AWS, Google Cloud, Cloudflare, Akamai	SWE, Cloud, Security	AWS Architecture Blog, Grokking
15	Design a Notification Service	Medium	Meta, Slack, Discord, Salesforce	SWE, Mobile, Cloud	Slack Engineering Blog, Grokking
16	Design Airbnb or Booking.com	High	Airbnb, Booking, Expedia, Tripadvisor	SWE, Full-stack, Search	Airbnb Engineering Blog, System Design Interview Vol 2
17	Design a Content Delivery Network (CDN)	High	Cloudflare, Akamai, Fastly, AWS	SWE, Infrastructure, Network	Cloudflare Blog, AWS Architecture
18	Design a Distributed Cache	Medium	Redis, Memcached, AWS, Google	SWE, Infrastructure, Cloud	Redis Architecture, Grokking
19	Design a Task Scheduler	Medium	Airflow, AWS, Google, Microsoft	SWE, Cloud, Data	Apache Airflow, AWS Architecture
20	Design a Distributed Message Queue	High	Kafka, RabbitMQ, AWS, Google	SWE, Cloud, Infrastructure	Kafka Architecture, AWS Architecture
21	Design a Distributed Logging System	Medium	Splunk, Elastic, Datadog, New Relic	SWE, DevOps, SRE	Elastic Blog, Splunk Architecture
22	Design Google Maps	High	Google, Apple, Uber, Tesla	SWE, Maps, Mobile	Google Maps Platform Blog, System Design Interview Vol 2
23	Design an AI Large Language Model (LLM) System	High	OpenAI, Google, Microsoft, Anthropic	SWE, ML, AI	OpenAI System Card, LLM Architecture Papers
24	Design a Real-time Collaboration Editor (like Google Docs)	High	Google, Microsoft, Notion, Coda	SWE, Frontend, Real-time	Google Research, System Design Interview Vol 2
25	Design a Stock Trading System	High	Robinhood, Intuit, Citadel, JPMorgan	SWE, Financial, Real-time	Robinhood Engineering Blog, System Design Interview Vol 1

Latest System Design Questions for 2025-2026

The system design landscape is rapidly evolving with new technologies and architectural patterns. Here are the most recent system design problems being asked in 2025-2026 interviews at top tech companies:

#	Problem	Complexity	Companies	Roles	Key Considerations
1	Design a Multi-Agent AI Orchestration System	Very High	OpenAI, Microsoft, Google, Anthropic	SWE-AI, ML Infra	Coordination protocols, safety mechanisms, observability, task delegation
2	Design an Edge Computing Platform for IoT	High	AWS, Google, Microsoft, Tesla	Cloud, IoT, Edge	Local processing, sync strategies, bandwidth optimization, hardware constraints
3	Design a Privacy-Preserving Analytics System	High	Apple, Meta, Google, Snap	Privacy, Data	Differential privacy, homomorphic encryption, federated analytics, compliance
4	Design a Real-time AI-assisted Coding Platform	High	GitHub, Microsoft, Google, JetBrains	SWE, Developer Tools	LLM integration, IDE extensions, model latency, context management
5	Design a Serverless Data Pipeline System	Medium	AWS, Google, Snowflake, Databricks	Data, Cloud	Event-driven processing, cost optimization, scaling, observability
6	Design a Voice-First Operating System	Very High	Amazon, Google, Apple, Meta	OS, Voice AI	Natural language understanding, ambient computing, privacy, context awareness
7	Design a Decentralized Social Network	High	Block, Consensys, Discord	Blockchain, Social	Content distribution, moderation, identity management, consensus mechanisms
8	Design a Spatial Computing OS	Very High	Apple, Meta, Microsoft, Magic Leap	AR/VR, OS	3D rendering, gesture recognition, spatial mapping, device limitations
9	Design a Low-latency Global ML Inference System	High	OpenAI, Google, Anthropic, Meta	ML Infra, Cloud	Load balancing, model serving, region optimization, model quantization
10	Design a Quantum Computing Interface	Very High	IBM, Google, Microsoft, Amazon	Quantum, Cloud	Quantum-classical integration, error correction, abstraction layers

AI-Native System Design Questions (New in 2026)

These questions reflect the shift toward AI-native architectures in 2026 interviews:

#	Problem	Complexity	Companies	Key Considerations
1	Design a Hallucination-Free Banking Chatbot	High	Stripe, JPMorgan, Google	Domain-constrained generation, citation verification, regulatory compliance
2	Design a Perplexity.ai / LLM-Powered Search Engine	Very High	Google, OpenAI, Anthropic	RAG + live web crawling, citation generation, streaming responses
3	Design an AI Co-pilot like GitHub Copilot	High	Microsoft, Google, JetBrains	Context management across files, latency-sensitive completion, model routing
4	Design an Image Generation Service (Midjourney/DALL-E)	High	OpenAI, Google, Meta	Queue management, GPU scheduling, content safety filtering at scale
5	Design a Feature Store for ML Models	High	Netflix, Uber, Airbnb	Batch vs real-time features, training-serving skew, feature versioning
6	Design Real-Time Fraud Detection System	High	Stripe, PayPal, Amazon	50ms latency at 50K TPS, continuous model updates, feature engineering
7	Design ML Model Monitoring in Production	Medium	All	Drift detection (data, concept, prediction), automated alerting, degradation response
8	Design an Autonomous AI Travel Booking Agent	High	OpenAI, Anthropic, Google	Orchestrator + tool gateway, credential management, rollback, risk-classified actions
9	Design a Hospital Voice Assistant	Very High	Google, Amazon, Apple	Multimodal (STT + LLM + TTS), HIPAA compliance, medical-context latency
10	Design a Conversational Recommender System	High	Netflix, Amazon, TikTok	Dialogue state tracking + recommendation engines

Emerging System Design Trends in 2025-2026

Several key trends are shaping system design interviews in 2025-2026:

1. AI Integration at Scale

   • Systems now commonly incorporate AI/ML components
   • Focus on handling model latency and unpredictability
   • Managing prompt engineering and context at scale
   • Robust handling of AI hallucinations and errors

2. Multi-Agent and Agentic Architectures (Major 2026 Shift)

   • Now a distinct interview category at senior/staff levels (Gartner: 60%+ enterprise AI apps will include agentic components by 2026)
   • Key components: orchestrator (observe-think-act loop), tool gateway with OpenAPI schemas, memory systems (working/episodic/semantic/procedural), policy/guardrails engine
   • Action risk classification: read-only, reversible-write, irreversible-write, external-communication
   • Tool gateway architecture: standardized schemas, credential management via secrets managers, sandboxed execution, distributed tracing
   • Model Context Protocol (MCP): Anthropic's open standard (Linux Foundation, co-founded with OpenAI and Block) for LLM-to-tool connections

3. Edge-Cloud Hybrid Systems

   • Processing sensitive data at the edge
   • Intelligent workload distribution
   • Handling intermittent connectivity
   • Resource-constrained optimization

4. Privacy-Preserving Architectures

   • Federated learning and analytics
   • Differential privacy implementations
   • Zero-knowledge proofs for verification
   • Data minimization and anonymization

5. Real-time Collaboration at Scale

   • Global distributed collaboration
   • Low-latency conflict resolution
   • Eventual consistency with immediate feedback
   • Multi-modal interaction (text, voice, visual)

Advanced System Design Concepts for 2025

To excel in 2025 system design interviews, candidates should be familiar with these advanced concepts:

1. Serverless and Function-as-a-Service Evolution

The serverless paradigm has evolved beyond simple functions to complex workflows:

• Stateful Serverless: Managing state in serverless architectures
• Serverless Workflows: Orchestration of complex function chains
• Cold Start Optimization: Techniques to minimize cold start latency
• FinOps for Serverless: Cost optimization strategies for serverless at scale

2. AI Infrastructure Design

With AI becoming central to most systems, understanding AI infrastructure is critical:

• Inference Optimization: Techniques like quantization, batching, and KV caching
• Model Lifecycle Management: Versioning, A/B testing, and progressive rollouts
• Prompt Engineering Infrastructure: Systems for managing and optimizing prompts
• Multi-Modal Integration: Combining text, image, audio, and video models

3. Distributed Systems Resilience

Modern distributed systems require sophisticated resilience strategies:

• Chaos Engineering: Designing systems that withstand unexpected failures
• Multi-Region Recovery: Cross-region failover and replication strategies
• Gray Failures: Detecting and handling partial system failures
• Backpressure Mechanisms: Elegant degradation under load

4. Data Mesh Architectures

Data architecture has evolved from centralized lakes to distributed ownership:

• Domain-Oriented Ownership: Distributing data ownership to domain experts
• Self-Serve Data Platforms: Enabling teams to consume data without bottlenecks
• Federated Governance: Maintaining consistency while distributing control
• Data Contracts: Establishing clear interfaces between data producers and consumers

5. Event-Driven Systems

Event-driven architecture has become the backbone of reactive, scalable systems:

• Event Sourcing at Scale: Practical implementations for large-scale systems
• CQRS Patterns: Separating read and write models for performance
• Stream Processing: Real-time analytics and processing of event streams
• Event Schema Evolution: Managing changes to event structures over time

Updated Interview Framework for 2025

The traditional system design interview framework has evolved to better assess candidates' ability to design modern systems:

1. Problem Exploration (5 minutes)

• Functional and non-functional requirements
• Scale, performance, and reliability expectations
• User profiles and access patterns
• New: AI/ML integration requirements
• New: Privacy and ethical considerations

2. High-Level Architecture (10 minutes)

• Core components and data flow
• API design and interfaces
• New: AI/ML component integration
• New: Edge-cloud distribution strategy

3. Component Deep Dive (15 minutes)

• Detailed design of 2-3 critical components
• Data models and schema design
• New: AI model selection and integration
• New: Privacy-preserving mechanisms

4. Scaling and Optimization (10 minutes)

• Horizontal vs. vertical scaling strategies
• Caching and performance optimizations
• New: AI inference optimization
• New: Cost optimization strategies

5. Operational Excellence (5 minutes)

• Monitoring and observability
• Deployment and rollback strategies
• New: Explainability and debugging
• New: Evolution and maintenance plans

6. Tradeoff Discussion (5 minutes)

• Explicit discussion of architectural tradeoffs
• Alternative approaches considered
• New: Ethical implications of design choices
• New: Future-proofing considerations

Resources for 2025 System Design Preparation

Here are the latest resources to prepare for system design interviews in 2025:

1. Books

   • "System Design for AI Engineers" (New for 2025)
   • "Distributed Systems in the Age of AI" (Updated for 2025)
   • "Edge Computing: Architectures, Applications and Technologies" (2024)
   • "Designing Data-Intensive Applications" (Still relevant with 2025 updates)

2. Engineering Blogs

   • OpenAI System Design Blog
   • Microsoft AI Architecture Patterns
   • Google Cloud Architecture Center
   • AWS Serverless Land
   • Uber Engineering (Edge Computing section)

3. Courses and Platforms

   • "AI System Design Interviews" on Educative
   • "Modern System Design for Software Engineers" (Updated for 2025)
   • "EdgeComputing.io" - Specialized learning platform
   • "AIInfrastructure.dev" - New practice platform

How to Stand Out in 2025 System Design Interviews

To truly excel in system design interviews in 2025, demonstrate these differentiating qualities:

1. Balance Theoretical and Practical Knowledge

   • Explain theoretical concepts but ground them in practical implementation details
   • Refer to real-world examples and case studies from industry

2. Showcase T-Shaped Knowledge

   • Demonstrate broad knowledge across multiple domains
   • Show deep expertise in at least one critical area (AI, distributed systems, etc.)

3. Incorporate Emerging Technologies Judiciously

   • Know when to apply new technologies vs. traditional approaches
   • Articulate clear reasoning for technology choices

4. Address Cross-Cutting Concerns

   • Proactively discuss security, privacy, and ethical considerations
   • Show awareness of regulatory requirements like GDPR, CCPA, or AI Act

5. Demonstrate Systems Thinking

   • Consider how components interact and affect the whole system
   • Anticipate emergent behaviors and failure modes

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Trending Coding Patterns for 2025

Beyond system design, coding interviews remain a crucial part of the technical interview process at top tech companies. Here are the most important coding patterns and questions trending in 2025 interviews:

High-ROI Coding Patterns for 2025

Focusing on these patterns will give you the highest return on investment for your interview preparation:

1. Two Pointers Technique

Applications: Arrays, strings, linked lists Key Problems:

• Two Sum variations (three sum, four sum)
• Container With Most Water
• Trapping Rain Water
• Palindrome verification
• Removing duplicates

Example 2025 Question:

Design an algorithm to find all unique quadruplets in an array that sum to a target, with O(n³) time complexity and optimized space usage.

2. Sliding Window

Applications: Arrays, strings, hash tables Key Problems:

• Maximum sum subarray of size K
• Longest substring with K distinct characters
• Minimum window substring
• Longest substring without repeating characters

Example 2025 Question:

Given a string and a pattern, find all start indices of pattern's anagrams in the string with optimal time and space complexity.

3. Tree & Graph Traversals (DFS/BFS)

Applications: Binary trees, graphs, matrices Key Problems:

• Path sum variations
• Binary tree level order traversal
• Course schedule (topological sort)
• Number of islands
• Word ladder

Example 2025 Question:

Design an algorithm to find the shortest path between two nodes in a weighted graph where weights represent time, but some edges can only be traversed during specific time windows.

4. Binary Search Variations

Applications: Sorted arrays, search space reduction Key Problems:

• Search in rotated sorted array
• Find first and last position of element
• Median of two sorted arrays
• Kth smallest element in a sorted matrix

Example 2025 Question:

Design an algorithm to find the kth smallest element in a row-wise and column-wise sorted 2D array with optimal time complexity.

5. Dynamic Programming with Optimizations

Applications: Optimization problems, counting problems Key Problems:

• Longest increasing subsequence
• Edit distance
• Coin change
• Unique paths
• Knapsack problem variants

Example 2025 Question:

Implement a space-optimized solution for the minimum cost to cut a rod into pieces of specific lengths, where each cut has a different cost.

6. Graph Algorithms (Advanced)

Applications: Social networks, routing, scheduling Key Problems:

• Network delay time
• Minimum spanning tree
• Strongly connected components
• Shortest path algorithms (Dijkstra's, Bellman-Ford)

Example 2025 Question:

Design an algorithm to find the most efficient way to connect multiple servers where connection costs vary based on data transfer rates and physical distance.

7. Interval Merging and Processing

Applications: Calendar scheduling, resource allocation Key Problems:

• Merge intervals
• Insert interval
• Meeting rooms
• Non-overlapping intervals

Example 2025 Question:

Implement an algorithm that can schedule optimal maintenance windows for a system with multiple components, each requiring different maintenance intervals.

Latest Coding Questions at Top Companies (2025)

Company	Question	Difficulty	Pattern
Google	Design a time-based key-value store with versioning and queryable history	Hard	Hash Table + Binary Search
Meta	Implement an algorithm to detect when a user's social feed should be refreshed based on friend activity patterns	Medium	Graph + Sliding Window
Amazon	Design an inventory management system that optimizes for both space utilization and retrieval time	Hard	Heap + DP
Microsoft	Implement a smart code autocomplete system that learns from user corrections	Hard	Trie + ML
OpenAI	Design an algorithm to detect and rank the relevance of hallucinated content in an LLM output	Hard	NLP + DP
Apple	Implement a privacy-preserving data structure for on-device analytics	Medium	Bloom Filter + Cryptography
Netflix	Design a content recommendation system that balances user preferences with content diversity	Hard	Graph + Prioritization
Uber	Optimize driver-to-rider matching in a dynamic environment with changing traffic conditions	Hard	Graph + Greedy

Preparation Strategy for 2025

1. Master the Fundamentals: Ensure you have a solid understanding of data structures, algorithms, and complexity analysis.

2. Pattern Recognition: Group problems by patterns rather than by data structures. This helps apply solutions across different contexts.

3. Practice Optimization: Don't stop at a working solution; focus on optimizing time and space complexity.

4. Mock Interviews: Schedule regular mock interviews to simulate real interview conditions.

5. Verbalize Your Thinking: Practice explaining your thought process while coding.

6. Learn from Solutions: After solving a problem, study multiple approaches to understand different perspectives.

7. Consistent Practice: Aim for consistent daily practice rather than cramming.

Advanced Topics to Master in 2025

• Quantum Algorithm Basics: Understanding quantum computing principles is becoming relevant for specific roles.
• AI/ML Algorithms: Familiarity with fundamental ML algorithms and data structures.
• Distributed Systems Coding: Problems involving distributed data structures and algorithms.
• Blockchain Data Structures: Understanding merkle trees, cryptographic hashes, and consensus algorithms.
• Edge Computing Optimizations: Algorithms optimized for resource-constrained environments.

By focusing on these patterns and topics, you'll be well-prepared for coding interviews at top tech companies in 2025.

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