nw-sd-framework

# System Design Framework ## The 4-Step Process Every system design follows this structure. Skipping steps is the top mistake. ### Step 1: Understand the Problem and Establish Design Scope (3-10 min) Narrow an impossibly broad question into a tractable problem. **Ask about**: users and scale | most important features | read/write ratio | non-functional requirements (latency, availability, consistency) | existing infrastructure | special constraints (mobile-first, offline, regulatory) **Produce**: functional requirements (3-5 bullets) | non-functional requirements (scale, latency, availability, consistency model) | capacity estimation (QPS, storage, bandwidth) **Red flags if skipped**: designing a system nobody asked for | over-engineering for imaginary scale | missing critical constraints (GDPR, real-time) ### Step 2: Propose High-Level Design and Get Buy-In (10-15 min) Sketch the big picture. Validate before diving deep. **Do**: draw architecture diagram (clients, servers, databases, caches, queues) | define API contract (REST/GraphQL/gRPC -- key endpoints) | design data model (entities, relationships, access patterns) | walk through 1-2 core use cases end-to-end | get buy-in: "Does this make sense before I go deeper?" **API patterns**: RESTful for CRUD-heavy | GraphQL for flexible client queries | gRPC for internal service-to-service | WebSocket/SSE for real-time **Data model**: SQL vs NoSQL based on access patterns, not hype | denormalization trade-offs | parti...