# nodejs-backend

A skill that lays out Node.js project structure and ready-made patterns for Express, Fastify and repositories. It kicks in when the agent edits code under src/api, src/routes or src/server.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 434 installs · ★ 711
- Author: alinaqi
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/alinaqi/maggy/tree/HEAD/skills/nodejs-backend/SKILL.md
- Updated: 2026-10-13
- HTML: https://affpapa.org/en/nevibecode/skills/nodejs-backend

## What it does

The skill describes a layered layout: `core` for pure business logic, `infra` for HTTP, database and third-party APIs, plus a separate `config`. It ships code samples the agent copies from — a route handler with `zod` validation, dependency injection at the composition root, domain error classes and a global Express error handler.

For data access it shows a repository pattern on `Kysely` and how to run transactions. Config is loaded through a `zod` schema that validates environment variables. Tests split into unit tests of the core with a mocked repository and integration tests through `supertest`.

Activation is path-based: `src/api/**`, `src/routes/**`, `src/server/**`, `src/middleware/**`, `server/**`, `api/**`. Keep your routes somewhere else and the skill will not load on its own — you call it by hand. The samples assume `zod`, `Kysely` and `supertest`, so on a different stack expect to rewrite them.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add alinaqi/maggy --skill nodejs-backend -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/nodejs-backend/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/nodejs-backend/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add alinaqi/maggy --skill nodejs-backend -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/nodejs-backend/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add alinaqi/maggy --skill nodejs-backend -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/nodejs-backend/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install alinaqi/maggy nodejs-backend
```

2. **Manually: put the files in place**
- File: `.github/skills/nodejs-backend/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add alinaqi/maggy --skill nodejs-backend -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/alinaqi/maggy --path skills/nodejs-backend
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/nodejs-backend/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add alinaqi/maggy --skill nodejs-backend -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/alinaqi/maggy/tree/HEAD/skills/nodejs-backend/SKILL.md

## When to use it
- split a Node.js backend into core, infra and config layers
- write an Express route handler with zod body validation
- build a repository and transactions on Kysely
- collect domain errors behind one global Express handler
- validate environment variables with a schema at startup

## Example prompts
- add a POST /users route following the nodejs-backend skill
- create an orders repository on Kysely like in nodejs-backend
- set up the global Express error handler from the skill

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 61d422d365a88912.

BEGIN THIRD-PARTY FILE 61d422d365a88912
````text
---
name: nodejs-backend
description: Node.js backend patterns with Express/Fastify, repositories
when-to-use: When working on Node.js backend code - API routes, middleware, server setup
user-invocable: false
paths: ["src/api/**", "src/routes/**", "src/server/**", "src/middleware/**", "server/**", "api/**"]
effort: medium
---

# Node.js Backend Skill


---

## Project Structure

```
project/
├── src/
│   ├── core/                   # Pure business logic
│   │   ├── types.ts            # Domain types
│   │   ├── errors.ts           # Domain errors
│   │   └── services/           # Pure functions
│   │       ├── user.ts
│   │       └── order.ts
│   ├── infra/                  # Side effects
│   │   ├── http/               # HTTP layer
│   │   │   ├── server.ts       # Server setup
│   │   │   ├── routes/         # Route handlers
│   │   │   └── middleware/     # Express middleware
│   │   ├── db/                 # Database
│   │   │   ├── client.ts       # DB connection
│   │   │   ├── repositories/   # Data access
│   │   │   └── migrations/     # Schema migrations
│   │   └── external/           # Third-party APIs
│   ├── config/                 # Configuration
│   │   └── index.ts            # Env vars, validated
│   └── index.ts                # Entry point
├── tests/
│   ├── unit/
│   └── integration/
├── package.json
└── CLAUDE.md
```

---

## API Design

### Route Handler Pattern
```typescript
// routes/users.ts
import { Router } from 'express';
import { z } from 'zod';
import { createUser } from '../../core/services/user';
import { UserRepository } from '../db/repositories/user';

const CreateUserSchema = z.object({
  email: z.string().email(),
  name: z.string().min(1).max(100),
});

export function createUserRoutes(userRepo: UserRepository): Router {
  const router = Router();

  router.post('/', async (req, res, next) => {
    try {
      const input = CreateUserSchema.parse(req.body);
      const user = await createUser(input, userRepo);
      res.status(201).json(user);
    } catch (error) {
      next(error);
    }
  });

  return router;
}
```

### Dependency Injection at Composition Root
```typescript
// index.ts
import { createApp } from './infra/http/server';
import { createDbClient } from './infra/db/client';
import { UserRepository } from './infra/db/repositories/user';
import { createUserRoutes } from './infra/http/routes/users';

async function main(): Promise<void> {
  const db = await createDbClient();
  const userRepo = new UserRepository(db);
  
  const app = createApp({
    userRoutes: createUserRoutes(userRepo),
  });
  
  app.listen(3000);
}
```

---
````
END THIRD-PARTY FILE 61d422d365a88912

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