Spring Boot Reference Documentation

What the Spring Boot reference is

Spring Boot is the most common way to build a Java web backend today, and this is its official reference, written by the Spring team. It describes how Boot sets up an application for you and every switch you have to change that behaviour. The current release in September 2026 is 4.1.1, which needs Java 17 or later and Spring Framework 7. The docs keep a version picker, so you can read the pages that match the version in your pom.xml or build.gradle.

What it covers

• Developing with Spring Boot: build systems, structuring your code, auto-configuration, beans and dependency injection, and packaging an app for production.
• Core features: SpringApplication, externalised configuration, profiles, logging, JSON and task scheduling.
• Web, data, IO and messaging: Spring MVC, SQL and NoSQL databases, caching, validation, REST clients, Kafka and more.
• Security: how Boot configures Spring Security, OAuth2 and SAML.
• Testing: the test starters, testing slices and Testcontainers support.
• Packaging: container images and GraalVM native images.
• Production-ready features: Actuator endpoints, health checks, metrics and tracing.
• How-to guides and an appendix listing every application property.

Is it worth reading when there are so many tutorials?

Yes, because Spring Boot changes between major versions and many tutorials online were written for Spring Boot 2 and Java 8. Starter names, package names (javax to jakarta) and test annotations have all moved since then. The reference is always correct for the version you select, and its how-to guides answer the everyday questions directly: how to change the port, use two data sources, run Flyway or turn off an auto-configuration. When something works "by magic", the auto-configuration chapter explains which condition switched it on.

How to use it without getting lost

1. Build one small app from a Spring guide or Spring Initializr first.
2. Read "Developing with Spring Boot" and the externalised configuration and profiles chapters.
3. Open the Data chapter when you connect PostgreSQL, and the Testing chapter when you write your first integration test.
4. Read the Actuator chapter before you deploy.
5. Keep the application properties appendix open as a lookup.

Prerequisites

Comfortable Java, including classes, interfaces, generics and annotations, and basic HTTP. You do not need to know the Spring Framework in depth first, but the dependency injection chapter makes more sense after you have written a service or two.

Common questions

Is it free? Yes. Spring Boot is open source under the Apache 2.0 licence, and the reference is free to read.

Reference or guides first? Guides first for a working app in an hour, then the reference to understand what you built.

What can I do after it? Configure a Spring Boot app for development and production with confidence, read startup errors, choose the right starters and expose safe health checks.

Best for: Java developers building REST APIs or full stack apps with Spring Boot who want the authoritative answer rather than a guess from an old forum post.