System Design Made Simple

An original learning series for technical blogs and interview preparation.

Edition: 1.4 · Updated: 26 September 2026

Preparing for an Enterprise Solutions Architect interview? Read the Enterprise Architect's Interview Framework first. It shows how the concepts in this series fit into an enterprise answer, and the payment system case study shows the full standard every case study is moving to.

Start with a familiar problem

Imagine a school library. Students want to find books, reserve a copy, and get a message when it is ready. One teacher can manage a small library with a notebook. A library used by many schools needs a better plan.

Software grows in much the same way. System design explains how to choose its parts, connect them, and keep them useful when traffic grows or something breaks.

The series uses short explanations first. More precise details follow under trade-offs, examples, and interview questions. Technical words are kept because interviewers use them, but each is explained in everyday language.

A map of the series

Read the five guides in order. Pick the case studies and the deep dives as you like:

flowchart TD
    S@{ icon: "algomi:svc-cube", label: "Start here: this overview", pos: "b", h: 52 }
    G1@{ icon: "algomi:svc-cube", label: "Guide 1: Foundations and data", pos: "b", h: 52 }
    S --> G1
    G2@{ icon: "algomi:svc-cube", label: "Guide 2: Networking and APIs", pos: "b", h: 52 }
    G1 --> G2
    G3@{ icon: "algomi:svc-cube", label: "Guide 3: Architecture and messaging", pos: "b", h: 52 }
    G2 --> G3
    G4@{ icon: "algomi:sec-shield", label: "Guide 4: Reliability, security, operations", pos: "b", h: 52 }
    G3 --> G4
    G5@{ icon: "algomi:svc-cube", label: "Guide 5: Interview workbook", pos: "b", h: 52 }
    G4 --> G5
    DD@{ icon: "algomi:svc-cube", label: "Deep dive: Ultra-resilient architecture", pos: "b", h: 52 }
    G4 -.-> DD
    DG@{ icon: "algomi:svc-cube", label: "Deep dive: gRPC", pos: "b", h: 52 }
    G2 -.-> DG
    CS@{ icon: "algomi:svc-cube", label: "Fifteen case studies, in any order", pos: "b", h: 52 }
    G5 --> CS