AI Chat Service

A Spring Boot middleware service that acts as a bridge between users and a Large Language Model (LLM) via OpenRouter.

Requirements

• Java 25
• Maven
• OpenRouter API key (free tier available at openrouter.ai)

Features

• Multiple AI personalities via system prompts
• Session-based conversation memory
• Automatic retry with exponential backoff
• Global error handling
• OpenAPI/Swagger documentation
• Chat UI with Markdown rendering

Setup

1. Clone the repository

git clone https://github.com/SandraNelj/ai-chat-service.git cd ai-chat-service

2. Configure your API key

Create a .env file in the project root:

OPENROUTER_API_KEY=your-api-key-here OPENROUTER_API_URL=https://openrouter.ai/api/v1 OPENROUTER_API_MODEL=openrouter/free

3. Run the application

./mvnw spring-boot:run

4. Access the application

• Chat UI: http://localhost:8080
• Swagger API docs: http://localhost:8080/swagger-ui.html

API

Endpoint: POST /api/v1/chat

Request body:

{ "personality": "helper", "message": "Hello!", "sessionId": "my-session-123" }

Personalities: helper, coder, pirate

Response:

{ "reply": "Hello! How can I help you?", "personality": "helper" }