JongYang: Zero to Hero

Everything you need to understand every line of the JongYang service booking platform — from how HTTP works to why we use bcrypt, from Docker networks to Next.js middleware. Work through the modules in order.

💡 How to use this: Open each page in order. Read the concept, study the real project code, draw the diagrams mentally, then test yourself with the quiz. When you can answer every quiz question without looking, move on. Bookmark your current page in the browser.

Module 1

The Foundation

How the Web Works

HTTP, REST APIs, JSON, status codes, and why we have a separate frontend and backend.

async/await, the event loop, and why FastAPI refuses to run synchronous code.

Module 2

Backend

Routers, Pydantic validation, dependency injection with Depends(), lifespan, and OpenAPI docs.

Databases & ORM

PostgreSQL, UUIDs, SQLAlchemy 2.x async sessions, relationships, and the M:M junction table.

Alembic Migrations

Schema versioning — how to safely change your database structure without destroying data.

bcrypt password hashing, JWT tokens, httpOnly cookies, and the admin login flow.

Module 3

External Services

Payments & Webhooks

PromptPay, Omise API, the booking state machine, HMAC-SHA256 signature verification.

LINE Login OAuth2 flow, push notifications, and reminder scheduling with timezone handling.

Module 4

Frontend

Components, useState, useEffect, useCallback, events, and 'use client' directive.

Next.js App Router

File-based routing, server vs client components, API routes, middleware, and subdomain rewriting.

Types, interfaces, union types, optional chaining, and how they mirror Pydantic models.

Utility-first CSS, responsive prefixes, state variants, and the project's design system.

Module 5

Infrastructure

Containers vs VMs, Dockerfile anatomy, multi-stage builds, and the npm version mismatch we hit.

Orchestrating postgres+fastapi+nextjs, health checks, two networks, and shared external networks.

Reverse proxy, automatic TLS certificates via ACME/Let's Encrypt, and wildcard DNS.

Module 6

Quality & Architecture

pytest fixtures, in-memory SQLite, httpx ASGITransport, and Playwright system tests.

Architecture Patterns

Multi-tenancy, subdomain routing, booking state machine, CORS, and the admin proxy pattern.

Putting It All Together

Full system diagram, end-to-end booking trace, glossary, and a 20-question final quiz.