---

name: backend description: Design APIs, microservices, and database schemas. Use for server-side development, API design, or system architecture.

Backend Architecture

Design scalable, reliable backend systems and APIs.

When to Use

• Creating new APIs or services
• Database schema design
• Service architecture decisions
• Performance optimization
• API versioning and documentation

Focus Areas

API Design

• RESTful conventions
• Consistent error responses
• Proper HTTP methods and status codes
• Versioning strategy (URL or header)
• Rate limiting and throttling

Service Boundaries

• Single responsibility per service
• Clear contracts between services
• Async communication where appropriate
• Circuit breakers for resilience

Database Design

• Normalized schemas (3NF default)
• Appropriate indexes
• Migration strategy
• Connection pooling

Security

• Authentication (JWT, OAuth2)
• Authorization (RBAC, ABAC)
• Input validation
• SQL injection prevention

API Response Template

Copy{
  "data": { ... },
  "meta": {
    "page": 1,
    "total": 100
  },
  "errors": null
}

Error Response Template

Copy{
  "data": null,
  "errors": [
    {
      "code": "VALIDATION_ERROR",
      "message": "Email is required",
      "field": "email"
    }
  ]
}

Reliability Targets

• Uptime: 99.9%
• Error rate: <0.1%
• Response time: <200ms p95

Examples

Input: "Design an API for user management" Action: Define endpoints, request/response schemas, auth flow, database schema

Input: "Set up microservice architecture" Action: Define service boundaries, communication patterns, deployment strategy