openui-forge-java

OpenUI Forge — Java

Build generative UI apps with a React frontend + Java Spring Boot (WebFlux) backend. The backend forwards OpenAI's SSE stream to the browser via a reactive WebClient and a Flux<String> controller, pairing with openAIAdapter() on the frontend.

Activation Triggers

• "openui java", "openui spring", "openui spring boot backend"
• "generative ui java", "java streaming ui backend", "webflux openui"

Prerequisites

• Node.js >= 22 (24 LTS recommended) + React >= 18.3.1 (19+ recommended) (frontend)
• Java 21 LTS recommended (Spring Boot 4.x requires Java 17+; it builds against Java up to 26)
• Maven 3.9+ (or Gradle 8+)
• Spring Boot 4.0.x (current stable line; 4.1.x is the latest). Boot 3.5.x also works but reached end of OSS support on 2026-06-30.
• OPENAI_API_KEY environment variable set

Quick Start

1. Create the React frontend and install OpenUI deps:

npm install @openuidev/react-ui @openuidev/react-headless @openuidev/react-lang lucide-react zod

1. Generate the system prompt into the backend's resources:

npx @openuidev/cli generate ./src/lib/library.ts --out backend/src/main/resources/system-prompt.txt

1. Create the Spring Boot backend (see Full Code below)
2. Run: mvn spring-boot:run on :8080, frontend on :3000

Full Code

Backend: backend/pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>4.0.6</version>
        <relativePath/>
    </parent>

    <groupId>com.example</groupId>
    <artifactId>openui-backend</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <properties>
        <java.version>21</java.version>
    </properties>

    <dependencies>
        <!-- WebFlux pulls in the reactive web stack, WebClient, and Reactor Netty -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>