OpenAPI and Spring-Boot 4 - What's New? by Badr Nass Lahsen @ Spring I/O 2026

This talk focuses on the advancements in Spring Boot 4, the leading Java framework for application development, highlighting its enhanced performance and cloud-native capabilities. The speaker explores key innovations such as built-in API versioning and improved integrations, emphasizing the significance of OpenAPI and its integration through springdoc-openapi. Core features discussed include support for the Scalar project, actuator integration, Javadoc reuse, HATEOAS, Data REST, and OAuth2 security. Additionally, the session examines historical version support, the impact of OpenAPI on developer experience, and the use of modern CI/CD tools like Gradle and Maven for API documentation. The speaker also addresses microservices use cases with Spring Cloud Gateway and serverless integration with Spring Cloud Function, providing valuable insights for those updating legacy APIs or creating new microservices.