Nodejs Backend Patterns

Seth HobsonCommunityCreated by Seth Hobson

Skill
Guidelines
Software development
MIT
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From the author

Build production-ready Node.js backend services with Express/Fastify, implementing middleware patterns, error handling, authentication, database integration, and API design best practices. Use when creating Node.js servers, REST APIs, GraphQL backends, or microservices architectures.

— the description by Seth Hobson

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides a structured approach to developing scalable and maintainable Node.js backend applications. It covers essential architectural patterns, such as layered architecture and dependency injection, alongside practical implementations for Express.js and Fastify. The guidance emphasizes production readiness through robust error handling, input validation, secure configuration, and efficient database integration for both SQL and NoSQL environments.

What it does

Defines layered architecture for clean separation of concerns
Provides setup patterns for Express.js and Fastify frameworks
Demonstrates dependency injection for improved testability
Outlines database integration patterns for PostgreSQL and MongoDB
Establishes best practices for security, logging, and performance
Offers guidance on request validation and structured error handling

When to use it

When architecting a new Node.js REST or GraphQL API
When refactoring existing services for better maintainability
When implementing authentication and authorization flows
When setting up database connection pooling and transaction management
When standardizing middleware and error handling across microservices

Advantages

Promotes type safety and maintainable code structures
Encourages modular design through dependency injection
Reduces boilerplate with proven architectural patterns
Improves application security and production reliability
Facilitates easier testing and resource management

Usage examples

“How should I structure my Node.js project to separate business logic from HTTP controllers?”: The agent will provide a layered architecture template, showing how to organize code into controllers, services, and repositories.
“Show me how to implement dependency injection in a Node.js service.”: The agent will provide a code example of a DI container that manages service and repository instances, improving testability.
“What is the best way to handle database connections in a production Node.js app?”: The agent will explain connection pooling for PostgreSQL or Mongoose connection management, including graceful shutdown procedures.
“How do I set up a basic Fastify server with schema validation?”: The agent will provide a Fastify boilerplate including plugin registration and route-level schema validation.

Install

Download the skill as a ZIP:
https://autogineer.com/agent-skills/wshobson/nodejs-backend-patterns/download

Unzip it into the cross-client skills folder of your project:

mkdir -p .agents/skills && unzip nodejs-backend-patterns.zip -d .agents/skills

Documentation by Seth Hobson

Node.js Backend Patterns

Comprehensive guidance for building scalable, maintainable, and production-ready Node.js backend applications with modern frameworks, architectural patterns, and best practices.

When to Use This Skill

Building REST APIs or GraphQL servers
Creating microservices with Node.js
Implementing authentication and authorization
Designing scalable backend architectures
Setting up middleware and error handling
Integrating databases (SQL and NoSQL)
Building real-time applications with WebSockets
Implementing background job processing

Detailed patterns and worked examples

Detailed pattern documentation lives in references/details.md. Read that file when the navigation tier above is insufficient.

Best Practices

Use TypeScript: Type safety prevents runtime errors
Implement proper error handling: Use custom error classes
Validate input: Use libraries like Zod or Joi
Use environment variables: Never hardcode secrets
Implement logging: Use structured logging (Pino, Winston)
Add rate limiting: Prevent abuse
Use HTTPS: Always in production
Implement CORS properly: Don't use * in production
Use dependency injection: Easier testing and maintenance
Write tests: Unit, integration, and E2E tests
Handle graceful shutdown: Clean up resources
Use connection pooling: For databases
Implement health checks: For monitoring
Use compression: Reduce response size
Monitor performance: Use APM tools

Testing Patterns

See javascript-testing-patterns skill for comprehensive testing guidance.

Files

ATTRIBUTION.mdAdded by AutoGineer1011 B
LICENSELicence file added by AutoGineer1.0 KiB
SKILL.md1.9 KiB
references/advanced-patterns.md9.2 KiB
references/details.md14.6 KiB

references/advanced-patterns.md

Node.js Advanced Patterns

Advanced patterns for dependency injection, database integration, authentication, caching, and API response formatting.

Dependency Injection

DI Container

// di-container.ts
import { Pool } from "pg";
import { UserRepository } from "./repositories/user.repository";
import { UserService } from "./services/user.service";
import { UserController } from "./controllers/user.controller";
import { AuthService } from "./services/auth.service";

class Container {
  private instances = new Map<string, any>();

  register<T>(key: string, factory: () => T): void {
    this.instances.set(key, factory);
  }

  resolve<T>(key: string): T {
    const factory = this.instances.get(key);
    if (!factory) {
      throw new Error(`No factory registered for ${key}`);
    }
    return factory();
  }

  singleton<T>(key: string, factory: () => T): void {
    let instance: T;
    this.instances.set(key, () => {
      if (!instance) {
        instance = factory();
      }
      return instance;
    });
  }
}

export const container = new Container();

// Register dependencies
container.singleton(
  "db",
  () =>
    new Pool({
      host: process.env.DB_HOST,
      port: parseInt(process.env.DB_PORT || "5432"),
      database: process.env.DB_NAME,
      user: process.env.DB_USER,
      password: process.env.DB_PASSWORD,
      max: 20,
      idleTimeoutMillis: 30000,
      connectionTimeoutMillis: 2000,
    }),
);

container.singleton(
  "userRepository",
  () => new UserRepository(container.resolve("db")),
);

container.singleton(
  "userService",
  () => new UserService(container.resolve("userRepository")),
);

container.register(
  "userController",
  () => new UserController(container.resolve("userService")),
);

container.singleton(
  "authService",
  () => new AuthService(container.resolve("userRepository")),
);

Database Patterns

PostgreSQL with Connection Pool

// config/database.ts
import { Pool, PoolConfig } from "pg";

const poolConfig: PoolConfig = {
  host: process.env.DB_HOST,
  port: parseInt(process.env.DB_PORT || "5432"),
  database: process.env.DB_NAME,
  user: process.env.DB_USER,
  password: process.env.DB_PASSWORD,
  max: 20,
  idleTimeoutMillis: 30000,
  connectionTimeoutMillis: 2000,
};

export const pool = new Pool(poolConfig);

// Test connection
pool.on("connect", () => {
  console.log("Database connected");
});

pool.on("error", (err) => {
  console.error("Unexpected database error", err);
  process.exit(-1);
});

// Graceful shutdown
export const closeDatabase = async () => {
  await pool.end();
  console.log("Database connection closed");
};

MongoDB with Mongoose

// config/mongoose.ts
import mongoose from "mongoose";

const connectDB = async () => {
  try {
    await mongoose.connect(process.env.MONGODB_URI!, {
      maxPoolSize: 10,
      serverSelectionTimeoutMS: 5000,
      socketTimeoutMS: 45000,
    });

    console.log("MongoDB connected");
  } catch (error) {
    console.error("MongoDB connection error:", error);
    process.exit(1);
  }
};

mongoose.connection.on("disconnected", () => {
  console.log("MongoDB disconnected");
});

mongoose.connection.on("error", (err) => {
  console.error("MongoDB error:", err);
});

export { connectDB };

// Model example
import { Schema, model, Document } from "mongoose";

interface IUser extends Document {
  name: string;
  email: string;
  password: string;
  createdAt: Date;
  updatedAt: Date;
}

const userSchema = new Schema<IUser>(
  {
    name: { type: String, required: true },
    email: { type: String, required: true, unique: true },
    password: { type: String, required: true },
  },
  {
    timestamps: true,
  },
);

// Indexes
userSchema.index({ email: 1 });

export const User = model<IUser>("User", userSchema);

Transaction Pattern

// services/order.service.ts
import { Pool } from "pg";

export class OrderService {
  constructor(private db: Pool) {}

  async createOrder(userId: string, items: any[]) {
    const client = await this.db.connect();

    try {
      await client.query("BEGIN");

      // Create order
      const orderResult = await client.query(
        "INSERT INTO orders (user_id, total) VALUES ($1, $2) RETURNING id",
        [userId, calculateTotal(items)],
      );
      const orderId = orderResult.rows[0].id;

      // Create order items
      for (const item of items) {
        await client.query(
          "INSERT INTO order_items (order_id, product_id, quantity, price) VALUES ($1, $2, $3, $4)",
          [orderId, item.productId, item.quantity, item.price],
        );

        // Update inventory
        await client.query(
          "UPDATE products SET stock = stock - $1 WHERE id = $2",
          [item.quantity, item.productId],
        );
      }

      await client.query("COMMIT");
      return orderId;
    } catch (error) {
      await client.query("ROLLBACK");
      throw error;
    } finally {
      client.release();
    }
  }
}

Authentication & Authorization

JWT Authentication

// services/auth.service.ts
import jwt from "jsonwebtoken";
import bcrypt from "bcrypt";
import { UserRepository } from "../repositories/user.repository";
import { UnauthorizedError } from "../utils/errors";

export class AuthService {
  constructor(private userRepository: UserRepository) {}

  async login(email: string, password: string) {
    const user = await this.userRepository.findByEmail(email);

    if (!user) {
      throw new UnauthorizedError("Invalid credentials");
    }

    const isValid = await bcrypt.compare(password, user.password);

    if (!isValid) {
      throw new UnauthorizedError("Invalid credentials");
    }

    const token = this.generateToken({
      userId: user.id,
      email: user.email,
    });

    const refreshToken = this.generateRefreshToken({
      userId: user.id,
    });

    return {
      token,
      refreshToken,
      user: {
        id: user.id,
        name: user.name,
        email: user.email,
      },
    };
  }

  async refreshToken(refreshToken: string) {
    try {
      const payload = jwt.verify(
        refreshToken,
        process.env.REFRESH_TOKEN_SECRET!,
      ) as { userId: string };

      const user = await this.userRepository.findById(payload.userId);

      if (!user) {
        throw new UnauthorizedError("User not found");
      }

      const token = this.generateToken({
        userId: user.id,
        email: user.email,
      });

      return { token };
    } catch (error) {
      throw new UnauthorizedError("Invalid refresh token");
    }
  }

  private generateToken(payload: any): string {
    return jwt.sign(payload, process.env.JWT_SECRET!, {
      expiresIn: "15m",
    });
  }

  private generateRefreshToken(payload: any): string {
    return jwt.sign(payload, process.env.REFRESH_TOKEN_SECRET!, {
      expiresIn: "7d",
    });
  }
}

Caching Strategies

// utils/cache.ts
import Redis from "ioredis";

const redis = new Redis({
  host: process.env.REDIS_HOST,
  port: parseInt(process.env.REDIS_PORT || "6379"),
  retryStrategy: (times) => {
    const delay = Math.min(times * 50, 2000);
    return delay;
  },
});

export class CacheService {
  async get<T>(key: string): Promise<T | null> {
    const data = await redis.get(key);
    return data ? JSON.parse(data) : null;
  }

  async set(key: string, value: any, ttl?: number): Promise<void> {
    const serialized = JSON.stringify(value);
    if (ttl) {
      await redis.setex(key, ttl, serialized);
    } else {
      await redis.set(key, serialized);
    }
  }

  async delete(key: string): Promise<void> {
    await redis.del(key);
  }

  async invalidatePattern(pattern: string): Promise<void> {
    const keys = await redis.keys(pattern);
    if (keys.length > 0) {
      await redis.del(...keys);
    }
  }
}

// Cache decorator
export function Cacheable(ttl: number = 300) {
  return function (
    target: any,
    propertyKey: string,
    descriptor: PropertyDescriptor,
  ) {
    const originalMethod = descriptor.value;

    descriptor.value = async function (...args: any[]) {
      const cache = new CacheService();
      const cacheKey = `${propertyKey}:${JSON.stringify(args)}`;

      const cached = await cache.get(cacheKey);
      if (cached) {
        return cached;
      }

      const result = await originalMethod.apply(this, args);
      await cache.set(cacheKey, result, ttl);

      return result;
    };

    return descriptor;
  };
}

API Response Format

// utils/response.ts
import { Response } from "express";

export class ApiResponse {
  static success<T>(
    res: Response,
    data: T,
    message?: string,
    statusCode = 200,
  ) {
    return res.status(statusCode).json({
      status: "success",
      message,
      data,
    });
  }

  static error(res: Response, message: string, statusCode = 500, errors?: any) {
    return res.status(statusCode).json({
      status: "error",
      message,
      ...(errors && { errors }),
    });
  }

  static paginated<T>(
    res: Response,
    data: T[],
    page: number,
    limit: number,
    total: number,
  ) {
    return res.json({
      status: "success",
      data,
      pagination: {
        page,
        limit,
        total,
        pages: Math.ceil(total / limit),
      },
    });
  }
}

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Security

No issues found by our static scan· No issues found

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Attribution and licence

Created by

Seth Hobson

Publisher

Seth Hobson (Community)

Source

wshobson/agents · plugins/javascript-typescript/skills/nodejs-backend-patterns · commit 4bde316

Licence

MIT License (redistribution allowed)

LICENSE (added by AutoGineer from LICENSE)
ATTRIBUTION.md (written by AutoGineer)

Synced

2026-11-09

AutoGineer is not affiliated with or endorsed by Seth Hobson or Seth Hobson.

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The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download nodejs-backend-patterns.zip