backend-patterns

name	backend-patterns
version	2.0.0
description	Production-grade backend patterns for Node.js, Python, Go, and Java/Spring frameworks
sasmp_version	1.3.0
bonded_agent	02-backend-patterns
bond_type	PRIMARY_BOND
atomic_design	{"single_responsibility":"Backend implementation patterns and frameworks","boundaries":{"includes":["nodejs","python","go","java","error_handling","middleware","async"],"excludes":["api_design","database_queries","infrastructure"]}}
parameter_validation	{"schema":{"type":"object","properties":{"language":{"type":"string","enum":["nodejs","python","go","java"]},"framework":{"type":"string"},"pattern":{"type":"string","enum":["middleware","error_handling","validation","logging"]}}}}
retry_config	{"enabled":true,"max_attempts":3,"backoff":{"type":"exponential","initial_delay_ms":1000,"max_delay_ms":30000}}
logging	{"level":"INFO","fields":["language","framework","pattern","duration_ms"]}
dependencies	{"skills":[],"agents":["02-backend-patterns"]}

Backend Patterns Skill

Purpose

Implement production-ready backend services with proper patterns.

Framework Selection

Language	Framework	Best For
Node.js	Express	Simple APIs, quick prototypes
Node.js	NestJS	Enterprise, TypeScript
Node.js	Fastify	High performance
Python	FastAPI	Modern async, auto-docs
Python	Django	Full-featured, admin
Go	Gin	Fast, middleware
Java	Spring Boot	Enterprise, ecosystem

Error Handling Pattern

// Error hierarchy
class AppError extends Error {
  constructor(
    public code: string,
    message: string,
    public status: number = 500,
  ) {
    super(message);
    this.name = this.constructor.name;
  }
}

class NotFoundError extends AppError {
  constructor(resource: string, id: string) {
    super(, , );
  }
}

    {
  () {
    (, , );
  }
}


app.( {
   (err  ) {
     res.(err.).({
      : ,
      : err.,
      : err.,
    });
  }
  logger.(err);
  res.().({ : , :  });
});