Vantage — A production‑grade, multi‑tenant SaaS platform for independent merchants – with distributed order orchestration, optimistic concurrency control, and statistical demand forecasting.

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Demo

web.mp4

Full walkthrough: login → dashboard → order search → low-stock fix → new product → AI demand forecast → developer portal.

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Why Vantage?

Vantage is a full‑stack demonstration of senior‑level engineering, designed to solve real‑world distributed systems problems:

• Multi‑tenant isolation – Hibernate @Filter guarantees zero data leakage between vendors.
• Flash‑sale concurrency – JPA @Version optimistic locking prevents overselling without database locks.
• Distributed Saga + Outbox – At‑least‑once delivery with compensating transactions (Chaos Monkey).
• Resilience4j – Circuit breakers, retries, bulkheads, and rate limiters for graceful degradation.
• End‑to‑end tracing – OpenTelemetry and Grafana Tempo stitch together every request and event.
• Statistical demand forecasting – Holt-Winters exponential smoothing with confidence intervals.

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Architecture Overview

graph TB
    subgraph Client
        React[React 19 SPA]
    end

    subgraph Backend
        API[Spring Boot 3.4 API]
        Worker[Spring Boot Async Workers]
    end

    subgraph Data
        PG[(PostgreSQL 16)]
        RMQ{{RabbitMQ}}
    end

    subgraph External
        Pay[Mock Payment Gateway]
        Geo[Nominatim]
        Grafana[Grafana Cloud]
    end

    React -- HTTPS/JWT --> API
    API -- JDBC/JPA --> PG
    API -- AMQP --> RMQ
    Worker -- AMQP --> RMQ
    Worker -- JDBC/JPA --> PG
    Worker -- HTTPS --> Pay
    Worker -- HTTPS --> Geo
    API -- OTLP --> Grafana
    Worker -- OTLP --> Grafana

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Technology Stack

Layer	Technologies
Backend	Java 21, Spring Boot 3.4, Spring Modulith, Hibernate, Flyway, JWT, Resilience4j
Frontend	React 19, TypeScript, Vite, TanStack Query, Tailwind CSS, Recharts, Leaflet
Infrastructure	PostgreSQL 16, RabbitMQ, Testcontainers, Docker Compose
Observability	Micrometer, OpenTelemetry, Grafana Tempo, Loki, Prometheus

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Quickstart (Local Development)

git clone https://github.com/elcoosp/vantage.git
cd vantage

# Start PostgreSQL and RabbitMQ
docker-compose up -d

# Run the backend
cd backend
./gradlew bootRun

# Run the frontend (in another terminal)
cd frontend
npm install
npm run dev

Open http://localhost:5173 and start exploring.

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Contributing

Please read our Contribution Guidelines and Code of Conduct before submitting pull requests.

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License

Proprietary – see LICENSE for details. EOF