micronaut-projects/micronaut-core

Micronaut is a modern, JVM-based full stack framework designed for building modular, easily testable applications with support for Java, Kotlin, and Groovy.

Micronaut addresses the overhead of traditional JVM frameworks by shifting framework infrastructure computation from runtime to compile time. Rather than using reflection, proxies, or runtime bytecode generation, the framework pre-computes dependency injection, aspect-oriented programming, and auto-configuration during compilation. This approach delivers fast startup times, reduced memory footprint, and minimal runtime overhead while maintaining the full feature set developers expect from a comprehensive framework.

Micronaut suits teams building microservices, serverless applications, or cloud-native systems where startup time and memory efficiency matter. It provides distributed configuration, service discovery, HTTP routing, and client-side load balancing alongside core capabilities like dependency injection and AOP. The framework is particularly valuable for containerized deployments and resource-constrained environments. Developers familiar with Spring, Spring Boot, or Grails will recognize the programming model, as the core team drew on experience building those frameworks to inform Micronaut's design.

The project maintains active development with regular updates to its core framework and ecosystem. The team sustains the codebase through the Micronaut Foundation and continues to expand language support and integration options. Documentation is comprehensive and kept current alongside releases. The project uses semantic versioning and clearly marks experimental or internal APIs, providing stability guarantees for production use.