# API and Interface Design

> Stable APIs, module boundaries, and public contracts

**Subcategory:** Workflow  
**License:** MIT  
**Source:** https://github.com/addyosmani/agent-skills/blob/main/skills/api-and-interface-design/SKILL.md

---

## When it is useful

Guides stable API and interface design. Use when designing APIs, module boundaries, or any public interface. Use when creating REST or GraphQL endpoints, defining type contracts between modules, or establishing boundaries between frontend and backend.

## The Catch

Encyclopedia When from addyosmani/agent-skills. Never-fire if the agent does not load it.