Micronaut is a lightweight JVM framework for building microservices. You write standard Java code: controllers (REST endpoints), services (business logic), repositories (data access). Micronaut compiles most "magic" at compile-time (not runtime), resulting in tiny, fast apps. A typical workflow: create project with mn create-app, add controller (annotated method), add service, add data layer (JPA/SQL/MongoDB), write integration tests with Testcontainers, compile to native binary with GraalVM. Deploy container or serverless function.