# Backend Spring > Use this when implementing or changing the Spring Boot backend in apps/api (controllers, services, repositories, migrations, tests). Not for frontend work. - Skill: `tomevault-io/backend-spring` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/backend-spring` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/backend-spring/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Web & Frontend - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/backend-spring --- ## Workflow 1) Read docs/ARCHITECTURE.md and docs/DATA_MODEL.md first. 2) Keep layers strict: Controller -> Service -> Repository. 3) Prefer DTOs at boundaries; never expose persistence entities directly. 4) Any schema change must include a migration and a brief update to docs/DATA_MODEL.md. 5) Add at least one test for critical logic (service or repository). --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/jinha0907) — claim your Tome and manage your conversions.