Generates Spring Boot 3.x configurations, creates REST controllers, implements Spring Security 6 authentication flows, sets up Spring Data JPA repositories, and configures reactive WebFlux endpoints. Use when building Spring Boot 3.x applications, microservices, or reactive Java applications; invoke

Spring Boot Engineer Core Workflow 1. Analyze requirements — Identify service boundaries, APIs, data models, security needs 2. Design architecture — Plan microservices, data access, cloud integration, security; confirm design before coding 3. Implement — Create services with constructor injection and layered architecture (see Quick Start below) 4. Secure — Add Spring Security, OAuth2, method security, CORS configuration; verify security rules compile and pass tests. If compilation or tests fail: review error output, fix the failing rule or configuration, and re run before proceeding 5. Test — Write unit, integration, and slice tests; run ./mvnw test (or ./gradlew test ) and confirm all pass before proceeding. If tests fail: review the stack trace, isolate the failing assertion or component, fix the issue, and re run the full suite 6. Deploy — Configure health checks and observability via Actuator; validate /actuator/health returns UP . If health is DOWN : check the components detail in the response, resolve the failing component (e.g., datasource, broker), and re validate Reference Guide Load detailed guidance based on context: Topic Reference Load When Web Layer references/web.md Controllers, REST APIs, validation, exception handling Data Access references/data.md Spring Data JPA, repositories, transactions, projections Security references/security.md Spring Security 6, OAuth2, JWT, method security Cloud Native references/cloud.md Spring Cloud, Config, Discovery, Gateway, resilience Testing references/testing.md @SpringBootTest, MockMvc, Testcontainers, test slices Quick Start — Minimal Working Structure A standard Spring Boot feature consists of these layers. Use these as copy paste starting points. Entity Repository Service (constructor injection) REST Controller DTO (record) Global Exception Handler Test Slice Constraints MUST DO Rule Correct Pattern Constructor injection public MyService(Dep dep) { this.dep = dep; } Validate API input @Valid @RequestBody MyRequest req on every mutating endpoint Type safe config @ConfigurationProperties(prefix = "app") bound to a record/class Appropriate stereotype @Service for business logic, @Repository for data, @RestController for HTTP Transaction scope @Transactional on multi step writes; @Transactional(readOnly = true) on reads Hide internals Catch domain exceptions in @RestControllerAdvice ; return problem details, not stack traces Externalize secrets Use environment variables or Spring Cloud Config — never application.properties MUST NOT DO Use field injection ( @Autowired on fields) Skip input validation on API endpoints Use @Component when @Service / @Repository / @Controller applies Mix blocking and reactive code (e.g., calling .block() inside a WebFlux chain) Store secrets or credentials in application.properties / application.yml Hardcode URLs, credentials, or environment specific values Use deprecated Spring Boot 2.x patterns (e.g., WebSecurityConfigurerAdapter ) [Documentation](https://jeffallan.github.io/claude skills/skills/backend/spring boot engineer/)

spring-boot-engineer