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Ad-hoc

This is a notebook for quick Q&A

Ad-hoc

No. Question Tags Note
1 01 Design a ChatGPT-style API Backend aaa-ais AI Infrastructure Systems —
2 02 RAG System at Scale Architecture Deep Dive aaa-ais AI Infrastructure Systems —
3 03 Vector Database Internals Explained aaa-ais AI Infrastructure Systems —
4 04 Embedding Pipeline Design for Large Systems aaa-ais AI Infrastructure Systems —
5 05 AI Inference Optimization at Scale aaa-ais AI Infrastructure Systems —
6 06 Batch vs Real-time LLM Inference Systems aaa-ais AI Infrastructure Systems —
7 07 Caching Strategies for LLM Responses aaa-ais AI Infrastructure Systems —
8 08 Token-based Billing Systems for AI APIs aaa-ais AI Infrastructure Systems —
9 09 Multi-model Routing System Design aaa-ais AI Infrastructure Systems —
10 10 AI Model Versioning Systems aaa-ais AI Infrastructure Systems —
11 11 Prompt Management System Design aaa-ais AI Infrastructure Systems —
12 12 LLM Observability System Design aaa-ais AI Infrastructure Systems —
13 13 AI Content Moderation Pipeline aaa-ais AI Infrastructure Systems —
14 14 AI Recommendation + LLM Hybrid System aaa-ais AI Infrastructure Systems —
15 15 Fine-tuning Pipeline System Design aaa-ais AI Infrastructure Systems —
16 16 Distributed GPU Scheduling Systems aaa-ais AI Infrastructure Systems —
17 17 Model Serving Infrastructure (Kubernetes + LLMs) aaa-ais AI Infrastructure Systems —
18 18 Latency Optimization for LLM APIs aaa-ais AI Infrastructure Systems —
19 19 Cost Optimization in AI Inference Systems aaa-ais AI Infrastructure Systems —
20 20 Building AI Agents Backend Architecture aaa-ais AI Infrastructure Systems —
21 01 How AI Agents Actually Work in Real Systems aaa-at AI Agents & Automation —
22 02 Agentic Workflow vs Traditional Backend Systems aaa-at AI Agents & Automation —
23 03 Building Multi-Agent Systems Architecture Explained aaa-at AI Agents & Automation —
24 04 Why AI Agents Fail in Production Systems aaa-at AI Agents & Automation —
25 05 Memory Systems in AI Agents Short-term vs Long-term aaa-at AI Agents & Automation —
26 06 Tool Calling Architecture in LLM Systems aaa-at AI Agents & Automation —
27 07 Planning vs Execution in AI Agents aaa-at AI Agents & Automation —
28 08 How AutoGPT-style Systems Are Built Internally aaa-at AI Agents & Automation —
29 09 Human-in-the-loop AI Systems Design aaa-at AI Agents & Automation —
30 10 State Management in AI Agents at Scale aaa-at AI Agents & Automation —
31 01 SLO SLA Error Budget aaa-ato Advanced / Trade-offs —
32 02 High Availability vs Consistency aaa-ato Advanced / Trade-offs —
33 03 Strong vs Eventual Consistency aaa-ato Advanced / Trade-offs —
34 04 Cassandra vs DynamoDB aaa-ato Advanced / Trade-offs —
35 05 SQL vs NoSQL Trade-offs aaa-ato Advanced / Trade-offs —
36 06 Read vs Write Optimization aaa-ato Advanced / Trade-offs —
37 07 Outbox Pattern aaa-ato Advanced / Trade-offs —
38 08 Data Modeling at Scale aaa-ato Advanced / Trade-offs —
39 09 Handling Hot Keys aaa-ato Advanced / Trade-offs —
40 10 Real-time vs Batch Systems aaa-ato Advanced / Trade-offs —
41 01 How to Approach Any System Design Interview aaa-ist Interview Strategy & Thinking —
42 02 The First 10 Minutes of System Design Interview aaa-ist Interview Strategy & Thinking —
43 03 How Senior Engineers Think About Trade-offs aaa-ist Interview Strategy & Thinking —
44 04 How to Structure a Perfect System Design Answer aaa-ist Interview Strategy & Thinking —
45 05 Common Mistakes in System Design Interviews aaa-ist Interview Strategy & Thinking —
46 06 How to Handle Unknown Requirements in Interviews aaa-ist Interview Strategy & Thinking —
47 07 Designing Under Ambiguity Real Interview Simulation aaa-ist Interview Strategy & Thinking —
48 08 What Interviewers Actually Evaluate in SD Interviews aaa-ist Interview Strategy & Thinking —
49 09 How to Ask the Right Questions in System Design aaa-ist Interview Strategy & Thinking —
50 10 Breaking Down Complex Systems in 5 Steps aaa-ist Interview Strategy & Thinking —
51 11 How to Estimate Scale in Interviews aaa-ist Interview Strategy & Thinking —
52 12 When to Choose Simple vs Complex Design aaa-ist Interview Strategy & Thinking —
53 13 How to Discuss Trade-offs Like a Senior Engineer aaa-ist Interview Strategy & Thinking —
54 14 How to Improve System Design Answers Fast aaa-ist Interview Strategy & Thinking —
55 15 Whiteboard Strategy for System Design Interviews aaa-ist Interview Strategy & Thinking —
56 16 How to Transition from Mid to Senior Engineer Thinking aaa-ist Interview Strategy & Thinking —
57 17 How to Explain Design Decisions Clearly aaa-ist Interview Strategy & Thinking —
58 18 How to Handle Interview Follow-up Questions aaa-ist Interview Strategy & Thinking —
59 19 System Design Interview Full Mock Walkthrough aaa-ist Interview Strategy & Thinking —
60 20 How to Pass Big Tech System Design Rounds aaa-ist Interview Strategy & Thinking —
61 01 How OpenAI-like LLM APIs Are Built aaa-llm LLM Infrastructure —
62 02 LLM Inference Pipeline Explained aaa-llm LLM Infrastructure —
63 03 Token-based Billing Systems Design aaa-llm LLM Infrastructure —
64 04 Caching Strategies for LLM Responses aaa-llm LLM Infrastructure —
65 05 Load Balancing for GPU-based Systems aaa-llm LLM Infrastructure —
66 06 Model Routing Systems GPT-4 vs Mini Models aaa-llm LLM Infrastructure —
67 07 Cost Optimization in LLM Serving Systems aaa-llm LLM Infrastructure —
68 01 Design an AI Chat Assistant System like ChatGPT aaa-psd AI Product & System Design —
69 02 Design an AI Search Engine like Perplexity aaa-psd AI Product & System Design —
70 03 Design an AI Coding Assistant like Copilot aaa-psd AI Product & System Design —
71 04 Design an AI Recommendation System with LLMs aaa-psd AI Product & System Design —
72 05 Design an AI Content Moderation System aaa-psd AI Product & System Design —
73 01 RAG Architecture Explained for Engineers aaa-rag RAG & Knowledge Systems —
74 02 Why RAG Beats Fine-tuning in Most Systems aaa-rag RAG & Knowledge Systems —
75 03 Vector Search vs Keyword Search Trade-offs aaa-rag RAG & Knowledge Systems —
76 04 Chunking Strategies in RAG Systems aaa-rag RAG & Knowledge Systems —
77 05 Embedding Pipeline Design in Production aaa-rag RAG & Knowledge Systems —
78 06 How Retrieval Systems Scale to Billion Documents aaa-rag RAG & Knowledge Systems —
79 07 Hybrid Search Systems BM25 + Vector Search aaa-rag RAG & Knowledge Systems —
80 08 Real time RAG vs Batch RAG Systems aaa-rag RAG & Knowledge Systems —
81 01 Intro to LLM Systems ai-a AI for Engineers e
82 02 Design RAG Architecture ai-a AI for Engineers e
83 03 Embeddings & Vector DB ai-a AI for Engineers e
84 04 Prompt Engineering Basics ai-a AI for Engineers e
85 05 AI Agent Design ai-a AI for Engineers e
86 06 LLM vs Traditional Systems ai-a AI for Engineers e
87 07 AI in Observability ai-a AI for Engineers —
88 08 AI for Alert Optimization ai-a AI for Engineers —
89 09 Building AI Backend Systems ai-a AI for Engineers —
90 10 MCP / Tooling / Integration ai-a AI for Engineers —
91 01 RAG Top-K Retrieval ai-lc AI LeetCode Patterns e
92 02 Embedding Similarity Search ai-lc AI LeetCode Patterns e
93 03 Agent Memory Cache ai-lc AI LeetCode Patterns e
94 04 Long-term Memory Retrieval ai-lc AI LeetCode Patterns e
95 05 Tool Routing ai-lc AI LeetCode Patterns e
96 06 Multi-step Agent Loop ai-lc AI LeetCode Patterns e
97 07 Context Compression ai-lc AI LeetCode Patterns e
98 08 Task Scheduling Agent ai-lc AI LeetCode Patterns e
99 09 Retry / Fallback Agent ai-lc AI LeetCode Patterns e
100 01 Design URL Shortener d&d-t System Design Deep Dive —
101 02 Design Twitter Timeline d&d-t System Design Deep Dive —
102 03 Design News Feed d&d-t System Design Deep Dive —
103 04 Design Chat System d&d-t System Design Deep Dive —
104 05 Design Notification System d&d-t System Design Deep Dive —
105 06 Design Rate Limiter d&d-t System Design Deep Dive —
106 07 Design Search System d&d-t System Design Deep Dive —
107 08 Design Logging System d&d-t System Design Deep Dive —
108 09 Design Metrics System d&d-t System Design Deep Dive —
109 10 Design Distributed Cache d&d-t System Design Deep Dive —
110 11 Design File Storage (S3-like) d&d-t System Design Deep Dive —
111 12 Design Video Streaming d&d-t System Design Deep Dive —
112 13 Design Ride Sharing (Uber) d&d-t System Design Deep Dive —
113 14 Design Food Delivery d&d-t System Design Deep Dive —
114 15 Design Ad System d&d-t System Design Deep Dive —
115 16 Design Recommendation System d&d-t System Design Deep Dive —
116 17 Design Payment System d&d-t System Design Deep Dive —
117 18 Design Inventory System d&d-t System Design Deep Dive —
118 19 Design Booking System d&d-t System Design Deep Dive —
119 20 Design Auction System d&d-t System Design Deep Dive —
120 21 Design Leaderboard d&d-t System Design Deep Dive —
121 22 Design Geolocation Service d&d-t System Design Deep Dive —
122 23 Design Event Tracking System d&d-t System Design Deep Dive —
123 24 Design Real-time Analytics d&d-t System Design Deep Dive —
124 25 Design Email System d&d-t System Design Deep Dive —
125 26 Design Web Crawler d&d-t System Design Deep Dive —
126 27. Design Collaborative Editing d&d-t System Design Deep Dive —
127 28 Design Multi-tenant System d&d-t System Design Deep Dive —
128 29 Design Feature Flag System d&d-t System Design Deep Dive —
129 30 Design API Gateway d&d-t System Design Deep Dive —
130 01 Two Pointers ld-c LeetCode Patterns —
131 02 Sliding Window ld-c LeetCode Patterns —
132 03 Prefix Sum ld-c LeetCode Patterns —
133 04 Binary Search ld-c LeetCode Patterns —
134 05 Fast & Slow Pointer ld-c LeetCode Patterns —
135 06 Stack Patterns ld-c LeetCode Patterns —
136 07 Monotonic Stack ld-c LeetCode Patterns —
137 08 BFS Basics ld-c LeetCode Patterns —
138 09 DFS Basics ld-c LeetCode Patterns —
139 10 Topological Sort ld-c LeetCode Patterns —
140 11 Backtracking ld-c LeetCode Patterns —
141 12 Dynamic Programming Intro ld-c LeetCode Patterns —
142 13 DP - Knapsack ld-c LeetCode Patterns —
143 14 DP - Sequence ld-c LeetCode Patterns —
144 15 DP - Grid ld-c LeetCode Patterns —
145 16 Greedy Algorithms ld-c LeetCode Patterns —
146 17 Heap - Priority Queue ld-c LeetCode Patterns —
147 18 Union Find ld-c LeetCode Patterns —
148 19 Trie ld-c LeetCode Patterns —
149 20 Segment Tree ld-c LeetCode Patterns —
150 21 Interval Problems ld-c LeetCode Patterns —
151 22 Bit Manipulation ld-c LeetCode Patterns —
152 23 Graph Shortest Path ld-c LeetCode Patterns —
153 24 Graph Cycle Detection ld-c LeetCode Patterns —
154 25 Tree Traversal Patterns ld-c LeetCode Patterns —
155 26 LCA ld-c LeetCode Patterns —
156 27 Binary Tree Patterns ld-c LeetCode Patterns —
157 28 String Matching (KMP) ld-c LeetCode Patterns —
158 29 Rolling Hash ld-c LeetCode Patterns —
159 30 Design Data Structures ld-c LeetCode Patterns —
160 1 How to Discuss Scaling in System Design? q&a-p Scaling & Architecture e
161 2 Core Load Balancing Framework q&a-p Scaling & Architecture e
162 3 How to Choose Cache Strategies in System Design? q&a-p Scaling & Architecture e
163 4 Core Content Delivery Framework q&a-p Scaling & Architecture —
164 10 Database vs Object Storage (S3) for Large Blob Storage in System Design q&a-p Data Layer Decisions —
165 5 Why Choose SQL vs NoSQL in System Design? q&a-p Data Layer Decisions c
166 6 Core Sharding Framework q&a-p Data Layer Decisions —
167 7 Replication in distributed systems q&a-p Data Layer Decisions —
168 08 Consistency Models- Strong vs Eventual in Practice q&a-p Data Layer Decisions —
169 09 CAP theorem q&a-p Data Layer Decisions —
170 11 Circuit Breaker vs Retry - Preventing Cascading Failures q&a-p System Resilience —
171 12 Timeouts and Retries - Tuning for Reliability q&a-p System Resilience —
172 13 How to Guarantee Idempotency in Distributed Systems? q&a-p System Resilience —
173 14 Rate Limiting- Fairness vs Throughput Trade-offs q&a-p System Design —
174 15 How to Guarantee Message Ordering in Distributed Message Queues? q&a-p Distributed Communication —
175 15 Message Queues- When to Use Async Systems q&a-p System Resilience —
176 16 Event-driven vs Request-response Architectures q&a-p System Resilience —
177 17 Exactly-once vs At-least-once Delivery Trade-offs q&a-p System Resilience —
178 18 Monolith vs Microservices- Evolution Strategy q&a-p Service Architecture —
179 19 Service Discovery- Client-side vs Server-side q&a-p Service Architecture —
180 20 API Design- Consistency vs Flexibility Trade-offs q&a-p Service Architecture —
181 21 Observability - Metrics vs Logs vs Traces Trade-offs q&a-p Observability —
182 01 ChatGPT System Design sd-llm Traditional SD to LLM System Design e
183 02 RAG System Design sd-llm Traditional SD to LLM System Design e
184 03 AI Agent System Design sd-llm Traditional SD to LLM System Design e
185 04 Memory System Design sd-llm Traditional SD to LLM System Design e
186 05 Tool Calling Architecture sd-llm Traditional SD to LLM System Design e
187 06 Context Window Management sd-llm Traditional SD to LLM System Design e
188 07 Hallucination Control System sd-llm Traditional SD to LLM System Design e
189 08 Evaluation System for LLM sd-llm Traditional SD to LLM System Design e
190 09 Cost Optimization for LLM sd-llm Traditional SD to LLM System Design e
191 10 Vector DB Scaling sd-llm Traditional SD to LLM System Design e
192 01 Active-active vs Active-passive sd-mds Modern Distributed Systems —
193 02 Global Traffic Routing GeoDNS vs Anycast sd-mds Modern Distributed Systems —
194 03 Data Locality in Distributed Systems sd-mds Modern Distributed Systems —
195 04 Multi-tenant Isolation Strategies sd-mds Modern Distributed Systems —
196 05 Cross-region Replication Latency vs Consistency sd-mds Modern Distributed Systems —
197 06 Regional Failure Handling Strategies sd-mds Modern Distributed Systems —
198 07 Global Load Balancing Architectures sd-mds Modern Distributed Systems —
199 08 Edge-first Architecture vs Cloud-first Systems sd-mds Modern Distributed Systems —
200 09 Data Sovereignty Constraints in System Design sd-mds Modern Distributed Systems —
201 10 Designing Systems under GDPR Constraints sd-mds Modern Distributed Systems —
202 11 Multi-cloud Architecture Trade-offs sd-mds Modern Distributed Systems —
203 12 Hybrid Cloud System Design sd-mds Modern Distributed Systems —
204 13 Disaster Recovery RPO vs RTO Trade-offs sd-mds Modern Distributed Systems —
205 14 Failover Strategies in Global Systems sd-mds Modern Distributed Systems —
206 15 Multi-region Database Design Patterns sd-mds Modern Distributed Systems —
207 16 Stateless vs Stateful Service Trade-offs sd-mds Modern Distributed Systems —
208 17 Placement Strategy in Distributed Systems sd-mds Modern Distributed Systems —
209 18 Regional Cache vs Global Cache sd-mds Modern Distributed Systems —
210 19 Cross-border Payment System Design sd-mds Modern Distributed Systems —
211 20 Real-world Multi-region Chat System sd-mds Modern Distributed Systems —
212 01 Latency Optimization in Distributed Systems sd-po Performance & Optimization —
213 02 Tail Latency Why P99 Matters More Than Average sd-po Performance & Optimization —
214 03 Cold Start Problem in Large Systems sd-po Performance & Optimization —
215 04 Memory vs CPU Trade-offs in Scaling sd-po Performance & Optimization —
216 05 Reducing Network Overhead in Microservices sd-po Performance & Optimization —
217 06 Database Connection Pool Optimization sd-po Performance & Optimization —
218 07 Read Replica vs Cache Optimization Strategy sd-po Performance & Optimization —
219 08 Compression vs Compute Trade-offs sd-po Performance & Optimization —
220 09 Batching vs Real-time Processing sd-po Performance & Optimization —
221 10 Backpressure in Streaming Systems sd-po Performance & Optimization —
222 11 Async Processing vs Sync Bottlenecks sd-po Performance & Optimization —
223 12 Reducing Cross-service Communication Cost sd-po Performance & Optimization —
224 13 Optimizing API Gateway Latency sd-po Performance & Optimization —
225 14 Cache Warm-up Strategies sd-po Performance & Optimization —
226 15 Avoiding N+1 Query Problems sd-po Performance & Optimization —
227 16 Optimizing Large-scale Pagination sd-po Performance & Optimization —
228 17 High-throughput Logging Systems sd-po Performance & Optimization —
229 18 Optimizing Serialization Formats (JSON vs Protobuf) sd-po Performance & Optimization —
230 19 Memory Leak Patterns in Distributed Systems sd-po Performance & Optimization —
231 20 CPU-bound vs IO-bound System Design sd-po Performance & Optimization —
232 01 How Stripe Handles Payment Consistency sd-rps Real Production Systems —
233 02 How Netflix Handles Video Delivery at Scale sd-rps Real Production Systems —
234 03 How TikTok Builds Recommendation Pipelines sd-rps Real Production Systems —
235 04 How Uber Dispatch System Works Internally sd-rps Real Production Systems —
236 05 How Airbnb Handles Search & Ranking sd-rps Real Production Systems —
237 06 How Amazon Handles Inventory Sync sd-rps Real Production Systems —
238 07 How Google Search Indexing Pipeline Works sd-rps Real Production Systems —
239 08 How YouTube Handles Video Upload Pipeline sd-rps Real Production Systems —
240 09 How Slack Handles Real-time Messaging sd-rps Real Production Systems —
241 10 How Notion Handles Collaborative Editing sd-rps Real Production Systems —
242 11 How Discord Scales Real-time Chat sd-rps Real Production Systems —
243 12 How Shopify Handles Flash Sales sd-rps Real Production Systems —
244 13 How PayPal Prevents Fraud at Scale sd-rps Real Production Systems —
245 14 How LinkedIn Builds Feed Ranking System sd-rps Real Production Systems —
246 15 How Instagram Handles Story Delivery sd-rps Real Production Systems —
247 16 How Twitter Handles Trending Topics sd-rps Real Production Systems —
248 17 How Cloudflare Handles Edge Requests sd-rps Real Production Systems —
249 18 How AWS S3 Achieves 99.999999999% Durability sd-rps Real Production Systems —
250 19 How GitHub Handles Large Repositories sd-rps Real Production Systems —
251 20 How OpenAI Serves LLM APIs at Scale sd-rps Real Production Systems —