Crafting Spring Boot Starters

Every Spring Boot developer consumes starters. Far fewer write them well.

Shipping a starter that other teams adopt, and still depend on a year later, takes more than an @AutoConfiguration class and a META-INF entry. It takes deliberate choices about defaults, extension points, conditional wiring, testability, observability, documentation, versioning, and release plumbing. Get any of those wrong and the starter quietly stops being used.

Crafting Spring Boot Starters walks through those choices end to end, on Spring Boot 4. You will build real starters across thirty-plus chapters, starting from a single-file auto-configuration that injects a request id, and finishing with a multi-module library that publishes its own BOM to Maven Central with versioned reference docs.

Along the way you will learn how to:

• Design auto-configuration that activates only when it should, and stays out of the way when it shouldn't.
• Expose SPI interfaces, customizer chains, and configuration properties that hold up in real applications.
• Test starters in isolation, in slices, and against Testcontainers, including how to write a test starter of your own.
• Instrument library code with Micrometer Observation, custom actuator endpoints, and health indicators.
• Lay out a Maven build that scales from a single module to an autoconfigure + starter + BOM split.
• Track Spring Boot versions, manage your own versioning, and publish releases through JReleaser.
• Write a README, samples folder, and reference site that turn a curious reader into an adopter.

The book is for Java developers who have shipped Spring Boot applications and now want to ship libraries. Every chapter is grounded in patterns from real production starters, rebuilt from scratch so you can read, run, and adapt the code yourself.