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name: backend-guide description: Complete backend development guide covering Node.js, Python, Go, Java, PHP, databases, APIs, authentication, and server architecture. Use when building server applications, APIs, or backend systems. sasmp_version: "1.3.0" bonded_agent: 02-backend-specialist bond_type: PRIMARY_BOND eqhm_enabled: true

Backend Development Guide

Build scalable, secure, and maintainable backend systems with comprehensive learning resources.

Quick Start

Choose your backend language journey:

Node.js (JavaScript)

// Express.js simple API
const express = require('express');
const app = express();

app.get('/api/users/:id', async (req, res) => {
  const user = await User.findById(req.params.id);
  res.json(user);
});

app.listen(3000, () => console.log('Server running'));

Python

# FastAPI example
from fastapi import FastAPI
from sqlalchemy.orm import Session

app = FastAPI()

@app.get("/users/{user_id}")
async def get_user(user_id: int, db: Session = Depends(get_db)):
    user = db.query(User).filter(User.id == user_id).first()
    return user

Go

// Gin framework example
package main

import "github.com/gin-gonic/gin"

func main() {
    r := gin.Default()

    r.GET("/api/users/:id", func(c *gin.Context) {
        user := getUser(c.Param("id"))
        c.JSON(200, user)
    })

    r.Run()
}

Backend Technology Paths

Node.js/JavaScript

• Frameworks: Express, Fastify, NestJS, Koa
• Package Manager: npm, yarn, pnpm
• Database Drivers: Mongoose, Sequelize, TypeORM
• Async: Promises, async/await, event loop

Python

• Frameworks: Django, Flask, FastAPI, Pyramid
• ORM: SQLAlchemy, Django ORM
• Async: asyncio, FastAPI async support
• Data Processing: NumPy, Pandas

Go

• Frameworks: Gin, Echo, Beego
• Concurrency: Goroutines, channels
• Standard Library: Excellent built-in packages
• Performance: Compiled, extremely fast

Java

• Frameworks: Spring Boot, Quarkus
• Build Tools: Maven, Gradle
• JVM Ecosystem: Comprehensive libraries
• Performance: Mature optimization

PHP

• Frameworks: Laravel, Symfony, Slim
• Database: Eloquent ORM, Doctrine
• Modern PHP: 8.0+, typed properties
• Deployment: Easy hosting, mature ecosystem

Database Fundamentals

Relational Databases

• PostgreSQL: Advanced features, JSON support, reliability
• MySQL: Wide adoption, good performance
• SQL Server: Enterprise choice

-- Design example
CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  email VARCHAR(255) UNIQUE NOT NULL,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE posts (
  id SERIAL PRIMARY KEY,
  user_id INTEGER REFERENCES users(id),
  title VARCHAR(255),
  content TEXT
);

NoSQL Databases

• MongoDB: Document-oriented, flexible schema
• Redis: In-memory, caching and sessions
• Cassandra: Distributed, high availability

Database Best Practices

• Normalization (1NF, 2NF, 3NF)
• Indexing strategy
• Query optimization
• Connection pooling
• Backup and recovery

API Development

REST APIs

// RESTful endpoints
GET    /api/users              # List all users
GET    /api/users/:id          # Get single user
POST   /api/users              # Create user
PUT    /api/users/:id          # Update user
DELETE /api/users/:id          # Delete user

GraphQL

• Schema design
• Resolvers and data fetching
• Query and mutation design
• Subscriptions for real-time data
• Performance optimization (batching, caching)

API Security

• Authentication (JWT, OAuth2, sessions)
• Authorization (RBAC, permissions)
• Rate limiting
• Input validation
• CORS configuration

Authentication & Authorization

Authentication Methods

// JWT Example
const token = jwt.sign({ userId: user.id }, SECRET, { expiresIn: '7d' });
const verified = jwt.verify(token, SECRET);

Authorization

• Role-Based Access Control (RBAC)
• Attribute-Based Access Control (ABAC)
• Permission scoping
• Token expiration strategies

Caching Strategies

HTTP Caching

• Cache headers (Cache-Control, ETag)
• Conditional requests (If-Modified-Since)
• Browser vs server caching

Application Caching

• Redis for session and data caching
• Cache invalidation strategies
• Cache warming
• Distributed caching

Testing

Unit Testing

• Test frameworks (Jest, pytest, unittest)
• Mocking dependencies
• Test coverage targets

Integration Testing

• Database testing
• API endpoint testing
• Third-party service mocking

Load Testing

• Tools (Apache JMeter, k6)
• Performance baselines
• Bottleneck identification

Deployment & DevOps

Containerization

• Docker for consistency
• Container orchestration (Kubernetes)
• CI/CD pipelines

Scaling

• Horizontal scaling (load balancing)
• Database replication
• Caching layers
• Microservices patterns

Learning Resources

Official Docs

• Node.js Docs
• Python Docs
• Go Official
• Spring Boot

Platforms

• FreeCodeCamp
• Udemy
• Frontend Masters
• Coursera

Projects

1. Blog API - CRUD, authentication
2. E-commerce Backend - Products, orders, payments
3. Real-time Chat - WebSockets, persistence
4. Job Board - Complex queries, filtering
5. Social Network - Relationships, feeds

Next Steps

1. Choose a language and framework
2. Master the language fundamentals
3. Learn database design
4. Build 5+ API projects
5. Study system design
6. Learn DevOps basics
7. Contribute to backend open-source

Roadmap.sh Reference: https://roadmap.sh/backend

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Status: ✅ Production Ready | SASMP: v1.3.0 | Bonded Agent: 02-backend-specialist