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Open Liberty

Open Liberty is an open source Java application server runtime (application platform) for building and running cloud-native, microservices, and enterprise Jakarta EE and MicroProfile applications.

  • Modular Java application server runtime for Jakarta EE and Eclipse MicroProfile workloads (application platform)
  • Implements Jakarta EE and MicroProfile specifications for enterprise web, transactional, and RESTful services (enterprise middleware)
  • Designed for containerized and cloud-native deployments, including integration with Kubernetes and Docker (cloud-native runtime)
  • Supports configuration, observability, and fault tolerance features defined in MicroProfile (microservices tooling)
  • Provides developer tooling integration with Maven, Gradle, and Integrated Development Environments (IDEs) through dev mode and build plugins (developer productivity)

More About Open Liberty

Open Liberty is an open source Java runtime (application server) from IBM for developing and operating enterprise applications that use the Jakarta EE and Eclipse MicroProfile programming models (enterprise middleware). It targets workloads that require standardized APIs for web applications, RESTful services, transactions, messaging, security, and other typical enterprise concerns while also supporting cloud-native deployment patterns.

The runtime is built as a modular, composable server where features can be enabled individually so that only the required components are included in a given server configuration (application platform). This feature-centric model lets architects assemble runtimes that support specific Jakarta EE profiles and MicroProfile capabilities such as RESTful services, CDI, JSON processing, persistence, messaging, and declarative security without loading unused components.

Open Liberty implements a range of Jakarta EE specifications (enterprise Java) that cover web application technologies, enterprise components, and integration services. These include APIs for servlets, JSP/JSF-style presentation, CDI-based dependency injection, JPA-based persistence, JTA transactions, JMS-style messaging, and Bean Validation, among others, as documented on the project site. At the same time, it provides implementations of Eclipse MicroProfile specifications (microservices framework), including configuration, health checks, metrics, fault tolerance, JWT-based security, Representational State Transfer (REST) clients, and OpenAPI integration.

The project is optimized for containerized and cloud-native environments (cloud-native runtime). Official documentation describes patterns for running Open Liberty images in Docker containers, integrating with Kubernetes and Red Hat OpenShift, and managing configuration through externalized properties and environment variables. Its fast start and dynamic configuration capabilities support iterative development and deployment workflows in Continuous Integration and Continuous Deployment (CI/CD) pipelines.

For developers, Open Liberty offers dev mode integrations for Maven and Gradle (developer tooling). These tools provide live reload of application code and configuration, automatic test execution, and simplified debugging workflows. The runtime also integrates with common Java IDEs through plug-ins and supports standard packaging models such as WAR and Export Administration Regulations (EAR), as well as modern microservice packaging using fat JARs or container images.

In enterprise environments, Open Liberty is used to host both traditional monolithic enterprise applications and microservices that expose HTTP/HTTPS APIs, message-driven components, and background workloads (enterprise application hosting). It interoperates with relational databases, messaging systems, and directory services via the standardized Jakarta EE APIs and common infrastructure protocols. It also supports TLS-based transport security, Role-Based Access Control (RBAC) using declarative security annotations, and integration with external identity providers through standard mechanisms where supported by Jakarta EE and MicroProfile specifications.

From a directory and taxonomy perspective, Open Liberty fits into the categories of Java application servers, Jakarta EE application platforms, and MicroProfile-compliant runtimes (enterprise middleware). It is relevant for organizations standardizing on Java-based application stacks for web, Application Programming Interface (API), and microservices workloads that require specification-compliant runtimes and alignment with cloud-native deployment practices.