Spring Boot Starters

A collection of production-ready Spring Boot auto-configuration libraries that help you integrate common infrastructure quickly, consistently, and with zero boilerplate.

---

Why custom starters?

As Spring-based systems grow, teams commonly face duplicated configuration across services, inconsistent observability, and boilerplate setup that slows down every new project. Custom Spring Boot starters solve this by packaging reusable infrastructure concerns into drop-in dependencies. Add a dependency. Get a working, production-ready setup — by default.

---

Available Starters

All artifacts are published under the io.github.saumilp.starters group. Each starter has its own README with configuration reference, DDL (where applicable), and usage examples.

Starter	Description	Config prefix	Version
spring-boot-starter-common	Shared exceptions, health-detail builder, and metric constants (no auto-configuration)	—	1.0.0
spring-boot-starter-redis	Redis templates, distributed locking, cache manager, health indicator, and Micrometer metrics	spring.redis	1.0.0
spring-boot-starter-minio	MinIO / S3-compatible object storage with health indicator and Micrometer metrics	spring.minio	2.0.0
spring-boot-starter-aws-s3	AWS S3 object storage via AWS SDK v2, pre-signed URLs, and a health indicator	spring.aws.s3	1.0.0
spring-boot-starter-rate-limiting	Annotation-driven distributed rate limiting backed by Redis, with an in-memory fallback	spring.rate-limit	1.0.0
spring-boot-starter-idempotency	HTTP idempotency enforcement via the Idempotency-Key header with Redis-backed response caching	spring.idempotency	1.0.0
spring-boot-starter-audit-log	Annotation-driven audit logging with pluggable sinks (log, JPA, composite)	spring.audit-log	1.0.0
spring-boot-starter-feature-flags	OpenFeature-based feature flag evaluation with file-based and Unleash providers	spring.feature-flags	1.0.0
spring-boot-starter-llm-client	OpenAI-compatible LLM client with retry, Micrometer metrics, and optional response caching	spring.llm	1.0.0
spring-boot-starter-multitenancy	Schema-per-tenant and DB-per-tenant multitenancy using Hibernate and tenant context propagation	spring.multitenancy	1.0.0
spring-boot-starter-outbox	Transactional Outbox pattern with JPA persistence and a pluggable Kafka / RabbitMQ relay	spring.outbox	1.0.0
spring-boot-starter-observability	Request correlation IDs, MDC log propagation, and async context propagation	spring.observability	1.0.0
spring-boot-starter-problem-details	Consistent RFC 7807 (application/problem+json) error responses with exception mapping	spring.problem-details	1.0.0
spring-boot-starter-resilient-client	Resilient outbound HTTP client with Resilience4j retry, circuit breaker, and timeouts	spring.resilient-client	1.0.0
spring-boot-starter-data-privacy	PII value/log masking and JPA field-level AES-GCM encryption	spring.data-privacy	1.0.0
spring-boot-starter-scheduler-lock	Distributed @Scheduled lock (in-memory or Redis) so a task runs on one instance only	spring.scheduler-lock	1.0.0
spring-boot-starter-secrets	Unified SecretSource over the environment and AWS Secrets Manager	spring.secrets	1.0.0
spring-boot-starter-notifications	Core notification SPI with pluggable email/SMS/push channels and a composite router	spring.notifications	1.0.0
spring-boot-starter-security-jwt	Opinionated JWT resource-server SecurityFilterChain with secure headers and CORS defaults	spring.security-jwt	1.0.0
spring-boot-starter-webhooks	Outbound webhook delivery with HMAC signing, retry/backoff, and dead-lettering	spring.webhooks	1.0.0
spring-boot-starter-api-keys	Issue / hash / validate / revoke API keys with an X-Api-Key enforcement filter	spring.api-keys	1.0.0

---

Quick Start

// Gradle (Kotlin or Groovy DSL)
dependencies {
    implementation 'io.github.saumilp.starters:spring-boot-starter-redis:1.0.0'
    implementation 'io.github.saumilp.starters:spring-boot-starter-minio:2.0.0'
}

<!-- Maven -->
<dependency>
    <groupId>io.github.saumilp.starters</groupId>
    <artifactId>spring-boot-starter-redis</artifactId>
    <version>1.0.0</version>
</dependency>

Each starter auto-configures itself on the classpath. Enable it, point it at your infrastructure via application.yml, and start using the injected beans — no @Configuration required.

---

Requirements

Requirement	Version
Java	21 LTS or later
Spring Boot	4.0.4 or later
Spring Framework	7.x (transitive via Boot)
Gradle (build)	9.x (wrapper provided)

---

Design Philosophy

Consumer-first. Every auto-configured bean is annotated @ConditionalOnMissingBean. Declare your own bean of the same type and the starter's default disappears completely.

No surprises. Starters never embed schema management (Flyway/Liquibase). If a starter requires a schema, it documents the DDL in its README and lets you run it.

Observable by default. Health indicators and Micrometer metrics are included in every starter that touches a remote service — conditional on the actuator / micrometer being present, so they add zero overhead if you don't use them.

Tested against real infrastructure. All integration tests use Testcontainers. If a test passes locally it will pass in CI.

For the internal design, module dependency graph, and auto-configuration mechanics, see ARCHITECTURE.md.

---

Project Structure

spring-boot-starters/
├── build.gradle.kts                       ← root build: BOM platform, toolchain, spotless, publishing, signing
├── settings.gradle.kts                    ← module registry + Foojay JDK toolchain resolver
├── gradle/wrapper/                        ← Gradle wrapper (9.x)
├── ARCHITECTURE.md                        ← design, module graph, and internals
├── DEVELOPER.md                           ← build, test, and contribution guide
├── CONTRIBUTING.md                        ← coding standards and PR process
├── CHANGELOG.md                           ← release history
│
├── spring-boot-starter-common/            ← shared abstractions (no auto-config)
├── spring-boot-starter-redis/             ← Redis utilities & distributed locking
├── spring-boot-starter-minio/             ← MinIO / S3-compatible object storage
├── spring-boot-starter-aws-s3/            ← AWS S3 (AWS SDK v2)
├── spring-boot-starter-rate-limiting/     ← distributed rate limiting
├── spring-boot-starter-idempotency/       ← HTTP idempotency
├── spring-boot-starter-audit-log/         ← annotation-driven audit logging
├── spring-boot-starter-feature-flags/     ← OpenFeature feature flags
├── spring-boot-starter-llm-client/        ← OpenAI-compatible LLM client
├── spring-boot-starter-multitenancy/      ← Hibernate multitenancy
├── spring-boot-starter-outbox/            ← transactional outbox
├── spring-boot-starter-observability/     ← correlation IDs & MDC propagation
├── spring-boot-starter-problem-details/   ← RFC 7807 error responses
├── spring-boot-starter-resilient-client/  ← Resilience4j HTTP client
├── spring-boot-starter-data-privacy/      ← PII masking & field encryption
├── spring-boot-starter-scheduler-lock/    ← distributed @Scheduled lock
├── spring-boot-starter-secrets/           ← unified secret source (env / AWS)
├── spring-boot-starter-notifications/     ← core notification SPI + composite router
├── spring-boot-starter-security-jwt/      ← JWT resource server + secure headers/CORS
├── spring-boot-starter-webhooks/          ← signed outbound webhook delivery
├── spring-boot-starter-api-keys/          ← API key issue/validate + enforcement filter
│
└── examples/                              ← runnable example applications (not published)
    ├── redis-example/
    ├── minio-example/
    ├── aws-s3-example/
    ├── rate-limiting-example/
    ├── idempotency-example/
    ├── audit-log-example/
    ├── feature-flags-example/
    ├── llm-client-example/
    ├── multitenancy-example/
    ├── outbox-example/
    ├── data-privacy-example/
    ├── notifications-example/
    ├── security-jwt-example/
    ├── webhooks-example/
    └── api-keys-example/

Every starter depends on spring-boot-starter-common and follows the same internal layout (config/, properties, service/util, and a META-INF/spring/...AutoConfiguration.imports registration). See ARCHITECTURE.md for the full breakdown.

---

Building Locally

./gradlew build                 # compile, unit tests, javadoc, spotless
./gradlew test                  # unit tests only (integration tests excluded)
./gradlew integrationTest       # integration tests (requires a running Docker daemon)
./gradlew javadoc               # generate and validate Javadoc (-Xdoclint:all)
./gradlew spotlessApply         # auto-format code
./gradlew publishToMavenLocal   # install all starters to ~/.m2 for local testing

Integration tests are tagged @Tag("integration") and are excluded from the test task. They are annotated @EnabledIfDockerAvailable, so they skip gracefully when no Docker daemon is present. See DEVELOPER.md for the full workflow.

---

Documentation

Document	Purpose
ARCHITECTURE.md	Module graph, auto-configuration mechanics, build & test architecture
DEVELOPER.md	Local setup, Gradle commands, adding a starter, Spring Boot 4.0 notes
CONTRIBUTING.md	Coding standards, commit conventions, PR process
CHANGELOG.md	Release history
Per-starter README.md	Configuration reference, DDL, and usage examples

---

Contributing

See CONTRIBUTING.md for coding standards, commit conventions, JavaDoc requirements, and how to submit a new starter. See DEVELOPER.md for the day-to-day build and test workflow.

---

License

Apache License 2.0 — see LICENSE for details.