System Design

⏱ 7 min read Core Entities Order: order_id, user_id, symbol, side (BUY, SELL), order_type (MARKET, LIMIT, STOP_LIMIT, TRAILING_STOP), quantity, limit_price, stop_price, status (PENDING, PARTIALLY_FILLED, […] Read article

⏱ 6 min read What Is a Feature Store? A feature store is a centralized platform for computing, storing, serving, and sharing ML features. Read article

⏱ 6 min read Core Entities Subscriber: subscriber_id, user_id, plan_id, status (ACTIVE, PAUSED, CANCELLED), billing_cycle_anchor, next_billing_date, shipping_address, preferences[], skip_count. Plan: plan_id, name, price_cents, billing_interval Read article

⏱ 6 min read Core Entities Restaurant: restaurant_id, name, address, geo_location, cuisine_type, is_open, prep_time_minutes, delivery_radius_km. MenuItem: item_id, restaurant_id, name, price_cents, category, is_available, customizations[]. Order: Read article

⏱ 6 min read Core Entities Provider: provider_id, name, specialty, clinic_id, npi_number, languages[], accepts_new_patients. ProviderSchedule: schedule_id, provider_id, day_of_week, start_time, end_time, slot_duration_minutes, is_active. Appointment: appointment_id, Read article

⏱ 6 min read RESTful Resource Modeling Resources are nouns, not verbs. POST /orders (create), GET /orders/{id} (read), PUT /orders/{id} (replace), PATCH /orders/{id} (partial Read article

⏱ 6 min read Core Entities Flight: flight_id, flight_number, airline_id, origin_airport, destination_airport, scheduled_departure, scheduled_arrival, actual_departure, actual_arrival, status (SCHEDULED, BOARDING, DEPARTED, ARRIVED, DELAYED, CANCELLED), aircraft_id, Read article

⏱ 6 min read WebRTC Fundamentals WebRTC (Web Real-Time Communication) enables peer-to-peer audio, video, and data transfer directly between browsers without a central media Read article

⏱ 6 min read Core Entities Member: member_id, user_id, tier (BRONZE, SILVER, GOLD, PLATINUM), points_balance, lifetime_points_earned, tier_qualifying_points_ytd, tier_expires_at, enrolled_at. PointTransaction: txn_id, member_id, txn_type (EARN, Read article

⏱ 6 min read Architecture Overview A multiplayer game backend handles: matchmaking (finding players with similar skill), game sessions (real-time state sync during a Read article

⏱ 6 min read Core Entities Patient: (patient_id, name, dob, allergies[], insurance_id, primary_care_provider_id). Prescription: (rx_id, patient_id, prescriber_id, drug_ndc, drug_name, dosage, quantity, days_supply, refills_remaining, written_date, Read article

⏱ 7 min read Core Entities Document: (doc_id, title, owner_id, workspace_id, current_version_id, status=ACTIVE|ARCHIVED|DELETED, created_at, updated_at). DocumentVersion: (version_id, doc_id, version_number, content_url, content_hash, size_bytes, created_by, created_at, Read article

⏱ 6 min read What Is an Online Judge? An online judge (LeetCode, HackerRank, Codeforces) accepts code submissions in multiple languages, executes them against Read article

⏱ 6 min read Requirements and Scale Search autocomplete suggests query completions as the user types. Design constraints: latency must be under 100ms (users Read article

⏱ 6 min read Core Entities Policy: (policy_id, policyholder_id, policy_type=AUTO|HOME|HEALTH|LIFE, coverage_amount_cents, premium_cents, deductible_cents, start_date, end_date, status=ACTIVE|EXPIRED|CANCELLED). Claim: (claim_id, policy_id, claimant_id, incident_date, reported_date, claim_type, description, Read article