# Api Design Principles

> Master REST and GraphQL API design principles to build intuitive, scalable, and maintainable APIs that delight developers. Use when designing new APIs, reviewing API specifications, or establishing API design standards.

Source: https://skillsagentes.com/skills/wshobson/agents/api-design-principles
Repository: https://github.com/wshobson/agents
Author: wshobson
License: MIT
Updated: hace 2 meses
Context cost: 55 tok installed, 901 tok once triggered, 9.8k tok with every bundled file
Bundle: 6 files, 38 KB
Permissions requested: none declared

## Install

```bash
npx -y skills add wshobson/agents --skill api-design-principles --agent claude-code
```

## What it does

- Aplica principios de diseño REST y GraphQL para construir APIs intuitivas, escalables y mantenibles
- Define convenciones de nombres, semántica HTTP y estrategias de versionado
- Cubre buenas prácticas como paginación, rate limiting, manejo de errores y documentación OpenAPI

## Use it when

- Diseñar nuevas APIs REST o GraphQL
- Refactorizar APIs existentes para mejorar su usabilidad
- Establecer estándares de diseño de API para un equipo
- Revisar especificaciones de API antes de implementarlas

## What triggers it

- "Ayúdame a diseñar una API REST para gestionar pedidos"
- "Revisa esta especificación GraphQL antes de implementarla"
- "¿Cómo debería versionar mi API pública?"
- "Necesito establecer estándares de diseño de API para mi equipo"

## Before you install

- Incluye un archivo references/details.md con patrones y ejemplos detallados para consultar cuando haga falta.

## Files

- SKILL.md — 4 KB
- assets/api-design-checklist.md — 4 KB
- assets/rest-api-template.py — 5 KB
- references/details.md — 10 KB
- references/graphql-schema-design.md — 9 KB
- references/rest-best-practices.md — 7 KB

## SKILL.md

Reproduced verbatim from wshobson/agents under MIT. This section is the upstream document and is in English.

# API Design Principles

Master REST and GraphQL API design principles to build intuitive, scalable, and maintainable APIs that delight developers and stand the test of time.

## When to Use This Skill

- Designing new REST or GraphQL APIs
- Refactoring existing APIs for better usability
- Establishing API design standards for your team
- Reviewing API specifications before implementation
- Migrating between API paradigms (REST to GraphQL, etc.)
- Creating developer-friendly API documentation
- Optimizing APIs for specific use cases (mobile, third-party integrations)

## Core Concepts

### 1. RESTful Design Principles

**Resource-Oriented Architecture**

- Resources are nouns (users, orders, products), not verbs
- Use HTTP methods for actions (GET, POST, PUT, PATCH, DELETE)
- URLs represent resource hierarchies
- Consistent naming conventions

**HTTP Methods Semantics:**

- `GET`: Retrieve resources (idempotent, safe)
- `POST`: Create new resources
- `PUT`: Replace entire resource (idempotent)
- `PATCH`: Partial resource updates
- `DELETE`: Remove resources (idempotent)

### 2. GraphQL Design Principles

**Schema-First Development**

- Types define your domain model
- Queries for reading data
- Mutations for modifying data
- Subscriptions for real-time updates

**Query Structure:**

- Clients request exactly what they need
- Single endpoint, multiple operations
- Strongly typed schema
- Introspection built-in

### 3. API Versioning Strategies

**URL Versioning:**

```
/api/v1/users
/api/v2/users
```

**Header Versioning:**

```
Accept: application/vnd.api+json; version=1
```

**Query Parameter Versioning:**

```
/api/users?version=1
```

## 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

### REST APIs

1. **Consistent Naming**: Use plural nouns for collections (`/users`, not `/user`)
2. **Stateless**: Each request contains all necessary information
3. **Use HTTP Status Codes Correctly**: 2xx success, 4xx client errors, 5xx server errors
4. **Version Your API**: Plan for breaking changes from day one
5. **Pagination**: Always paginate large collections
6. **Rate Limiting**: Protect your API with rate limits
7. **Documentation**: Use OpenAPI/Swagger for interactive docs

### GraphQL APIs

1. **Schema First**: Design schema before writing resolvers
2. **Avoid N+1**: Use DataLoaders for efficient data fetching
3. **Input Validation**: Validate at schema and resolver levels
4. **Error Handling**: Return structured errors in mutation payloads
5. **Pagination**: Use cursor-based pagination (Relay spec)
6. **Deprecation**: Use `@deprecated` directive for gradual migration
7. **Monitoring**: Track query complexity and execution time

## Common Pitfalls

- **Over-fetching/Under-fetching (REST)**: Fixed in GraphQL but requires DataLoaders
- **Breaking Changes**: Version APIs or use deprecation strategies
- **Inconsistent Error Formats**: Standardize error responses
- **Missing Rate Limits**: APIs without limits are vulnerable to abuse
- **Poor Documentation**: Undocumented APIs frustrate developers
- **Ignoring HTTP Semantics**: POST for idempotent operations breaks expectations
- **Tight Coupling**: API structure shouldn't mirror database schema

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Skills Agentes — https://skillsagentes.com/skills/wshobson/agents/api-design-principles