Express for FE devsFor front-end developers

Notes-style walkthrough of Express.js - from hello world to JWT auth, Prisma, sessions, files, WebSockets, and caching.

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Cheatsheet

You already speak HTTP

fetch, status codes, JSON, CORS - you use them from the browser. Express is the other side of that wall, in TypeScript.

Basics → practical backend

Routing and middleware first, then auth, ORM, sessions, file CRUD, and WebSockets.

FE mental maps

Middleware ≈ interceptors. Routers ≈ route configs. req/res ≈ the Request/Response you already know from fetch.

Who this is for

I've written this as if I'm leaving notes for myself - a front-end person who ships React/Vue/Svelte (or plain JS), knows fetch and SPA routing, and keeps wondering what actually sits behind /api/login.

If Next.js route handlers or Nuxt server routes feel a bit magical and you want the unbundled Express version of that story, you're in the right place. 🙂

How to follow along

Install Node.js 20+ LTS (Setup)
Read chapters in order - later ones assume earlier mental models
Run stuff from examples/notes-api when a chapter points at it
Keep the cheatsheet open once you're past the HTTP layer

bash

npm install
npm run docs:dev

And for the companion API:

bash

cd examples/notes-api
npm install
cp .env.example .env
npm run dev

What's intentionally missing

Nest / Fastify deep dives (pointed at in What next)
OAuth / social login
Production email providers (SES, SendGrid…) beyond "here's the hook"
Multi-node WebSocket scaling / Redis adapters (sketched in What next)
Deploy / Docker / K8s ops rabbit holes

We're here so you can open an Express codebase, find the route, follow the middleware, touch the user row, and not feel lost.

Wish you all the best - hope you're gonna enjoy the ride.

Best,

-- ł.