add-backend-developmentlisted

# Backend Development <!-- uses: - mention: add-backend-architecture - mention: add-database-development - mention: add-frontend-development - mention: add-project-scaffolding - mention: add-security-audit --> Skill for backend API implementation following universal architectural principles. **Use for:** Routes/Controllers, Services, DTOs, Domain logic, Data access, Error handling **Not for:** Frontend (`ux-design`), Database migrations (`database-development`), Security (`security-audit`) **Stack resolution:** Consult `CLAUDE.md ## Architecture Contract` for the framework in use (Express, Fastify, NestJS, Hono, Elysia, etc.). Apply these principles using the framework's idiomatic patterns. The AI already knows each framework's syntax — this skill teaches architecture, not framework tutorials. **Reference:** Always consult `CLAUDE.md` for general project standards. --- ## When NOT to Use - **Frontend / UI work** — use `ux-design` or `add-frontend-development` instead - **Database migrations or schema design** — use `add-database-development` - **Security audits / threat modeling** — use `add-security-audit` - **Pure scripts, CLIs, or non-API code** — these patterns target HTTP API services - **Greenfield architecture decisions** — use `add-backend-architecture` to choose structure first - **Project scaffolding** — use `add-project-scaffolding` for initial setup --- ## Clean Architecture ``` domain → application → infrastructure → presentation ``` | Layer | Allowed