Apache Sling
Apache Sling is a RESTful web framework built on top of the Java Content Repository (JCR) standard. It maps HTTP requests to content resources using a resource-oriented URL decomposition model and uses scripts or servlets to render responses, supporting multiple scripting languages including HTL, JSP, Groovy, and server-side JavaScript. Apache Sling forms the foundation of Adobe Experience Manager (AEM) and is an Apache Software Foundation project with 300+ modular OSGi bundles.
APIs
Apache Sling Resource API
The Sling Resource API provides RESTful access to JCR content repository nodes via HTTP. Every content node is addressable as a URL, supporting GET, POST, PUT, DELETE, and MOVE ...
Apache Sling Scripting API
The Sling Scripting API enables server-side rendering through multiple scripting engines. Scripts are resolved from the content repository based on resource type and selectors, ...
Apache Sling Event API
The Sling Event API provides a job processing and eventing system built on OSGi EventAdmin. It supports distributed job queuing, scheduled job execution, event broadcasting acro...
Features
Every JCR node is a REST resource accessible via URL with GET, POST, PUT, DELETE operations.
Flexible URL decomposition into resource path, selectors, extension, and suffix for content negotiation.
Powerful POST servlet for content CRUD operations, supporting create, modify, delete, move, copy, and import.
Server-side rendering with HTL, JSP, Groovy, FreeMarker, Thymeleaf, and Rhino JavaScript.
300+ modular OSGi bundles with hot-deploy capability and dynamic configuration.
Sling Resource Type system enables component inheritance and script resolution.
Distributed job queue and event system for asynchronous content processing.
Extensible health check system for monitoring Sling instance components.
Content distribution bundles for replicating content between Sling instances.
Use Cases
Build REST-based CMS solutions with JCR-backed content repositories.
Foundation framework for AEM digital experience platform implementations.
Serve structured JSON content via Sling's resource API for headless front-end applications.
Build OSGi-based Java web applications with RESTful resource routing.
Manage and serve digital assets stored in JCR with metadata and rendition support.
Integrations
Apache Sling is the foundational framework for Adobe Experience Manager (AEM).
JCR implementation providing the content repository backend for Sling.
OSGi framework container that hosts Sling bundles and manages the service registry.
OSGi runtime alternative for deploying Sling-based applications.
Maven plugin (slingstart-maven-plugin) and Maven archetypes for Sling development.
Search integration for indexing JCR content via Sling's indexing framework.