A modern, lightweight Java web framework for rapid application development

FusionKit is a comprehensive Java web framework that combines the best tools and libraries into a cohesive, easy-to-use package. Built on top of battle-tested technologies like Javalin, Freemarker, and HikariCP, it provides everything you need to build modern web applications quickly and efficiently.

• Lightweight & Fast - Built on Javalin for optimal performance
• Convention over Configuration - Sensible defaults with full customization
• Type-Safe Configuration - TOML-based configuration with strong typing
• Production Ready - Comprehensive logging and error handling

• Connection Pooling - HikariCP for high-performance database connections
• ORM Utilities - Simple mapping from ResultSets to Java objects
• MySQL Support - Optimized for MySQL with timezone handling

• Freemarker Integration - Powerful template engine with full feature support
• Static File Serving - Efficient static asset handling
• Internationalization - Built-in localization support
• Error Pages - Beautiful, customizable error handling

• Interactive Debugger - Built-in web-based debug console
• Route Overview - Visual route mapping and debugging
• Structured Logging - Logback integration with configurable levels

FusionKit follows a clean, organized directory structure:

your-app/ ├── .config/ # Configuration files │ ├── database.toml # Database configuration │ ├── freemarker.toml # Template engine settings │ └── fusionkit.toml # Framework configuration ├── src/main/java/ # Java source code ├── templates/ # Freemarker templates ├── public/ # Static assets (CSS, JS, images) ├── data/ # Application data files └── logs/ # Application logs 

<dependency> <groupId>com.github.marcandreher</groupId> <artifactId>fusionkit</artifactId> <version>1.1.3</version> </dependency>

public class App extends FusionKit { public static void main(String[] args) { // Initialize configuration FusionKit.setConfig(new AppConfig()); AppConfig config = (AppConfig) FusionKit.getConfig().getModel(); // Set up logging FusionKit.setLogLevel(config.getServer().getLogger()); // Configure database Database db = new Database(); db.connectToMySQL( config.getDatabase().getHost(), config.getDatabase().getUser(), config.getDatabase().getPassword(), config.getDatabase().getDatabase(), ServerTimezone.valueOf(config.getDatabase().getTimezone()) ); // Configure web application WebAppConfig webAppConfig = WebAppConfig.builder() .name("MyApp") .port(config.getServer().getPort()) .domain(config.getServer().getDomain()) .staticfiles(true) // Enable static file serving .freemarker(true) // Enable Freemarker templating .i18n(true) // Enable internationalization .productionLevel(ProductionLevel.DEVELOPMENT) .build(); // Register and start the application FusionKit.registerWebApplication(new MyWebApplication(webAppConfig)); } }

public class MyWebApplication extends WebApplication { public MyWebApplication(WebAppConfig config) { super(config); } @Override public void routes() { // Define your routes get("/", ctx -> ctx.render("index.ftl")); get("/api/users", UserController::getAllUsers); post("/api/users", UserController::createUser); } }

FusionKit includes a powerful web-based debug console accessible via:

• Press F10 to toggle the debug console
• View application state, logs, and model data
• Interactive JavaScript console for runtime debugging

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the project
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

This project is licensed under the MIT License - see the LICENSE file for details.

Marc Andre Herpers - @marcandreher

⭐ Star this repository if you find it helpful!