cem
Getting Started

Install & scaffold

Spin up a production-ready Express + TypeScript backend in under a minute.

Prerequisites

  • Node.js v18+
  • One of: npm v9+, yarn v1.22+, pnpm v8+, or bun v1.0+
  • A database (MongoDB, PostgreSQL) — local or cloud

Install the CLI (recommended)

Installing globally gives you the short cem executable everywhere in your workspace:

bash
# npm (recommended)
npm install -g create-express-modular

# yarn / pnpm / bun
yarn global add create-express-modular
pnpm add -g create-express-modular
bun add -g create-express-modular

Scaffold a new project

bash
cem my-api

Or run it without installing anything:

bash
# npm
npx create-express-modular my-api

# yarn
yarn create express-modular my-api

# pnpm
pnpm dlx create-express-modular my-api

# bun
bunx create-express-modular my-api

The wizard

The CLI asks you a handful of questions to tailor the generated project:

bash
? Project name: my-api
? Database / ORM: Mongoose  (MongoDB)
? Validator: Zod  (recommended)
? Include JWT Auth module? Yes
? Auth token delivery: HTTP-only cookies  (recommended)
? Include Docker setup? Yes
? Include Swagger API docs (OpenAPI 3.0)? Yes

What the CLI does next

  • Checks for an existing folder name upfront so nothing is overwritten
  • Scaffolds a clean, domain-driven folder structure
  • Generates DB config, error handling, the cem-cli.json manifest, .env, and .env.example
  • Runs a single-pass ultra-fast dependency install (pre-populated version pins)
  • Initialises a git repository

Project structure

CEM generates an opinionated, domain-driven layout:

my-api/
├── src/
│   ├── app/
│   │   ├── config/index.ts          # typed, centralized config
│   │   ├── config/swagger.ts        # OpenAPI 3.0 spec generator (Swagger only)
│   │   ├── errors/                  # AppError + Mongoose handler
│   │   ├── middlewares/             # auth, rate-limit, error, 404
│   │   ├── modules/                 # feature modules (auto-wired)
│   │   │   └── Auth/
│   │   ├── routes/index.ts          # router registry
│   │   └── utils/                   # catchAsync, sendResponse, QueryBuilder...
│   ├── app.ts                       # Express app
│   └── server.ts                    # DB + listen
├── .env / .env.example
├── cem-cli.json                     # CEM manifest (tracks stack & features)
├── Dockerfile / docker-compose.yml
└── package.json

Run it

bash
cd my-api
npm install
cem dev

Open http://localhost:5000 — you'll see CEM's branded welcome page with live metadata, a clickable health check, and a link to the interactive Swagger docs at /docs.