RentIt+ is a completed HTL diploma project: a rental and inventory management system with a JavaFX desktop client, a web administration interface, and a Spring Boot backend. The desktop client stores operational data in SQLite and synchronizes local changes with a central PostgreSQL database.
I created this companion repository to present RentIt+ through its architecture, workflows, desktop releases, and engineering decisions. The project was developed as an HTL diploma project by Brian Rono and Babak Nourbakhsh. The application source remains private; this repository provides a public view of how the system works.
Download Desktop v1.2.3 · Web SPA · Portfolio
The web order queue shows preparation progress and order details for the selected location.
| Platform | Installer |
|---|---|
| macOS | RentIt+.Desktop-1.2.3.dmg |
| Windows | RentIt+.Desktop-1.2.3.exe |
| Linux, amd64 | rentitplus-desktop_1.2.3_amd64.deb |
Version 1.2.3 updates the production API address and migrates existing desktop configurations that use the retired production endpoint. See the installation and upgrade guide for setup, checksums, and the macOS notarization limitation.
GitHub's automatic Source code archives contain this companion repository only, not the application source or installers.
Rental operations involve several related decisions: what stock is available at a location, which physical unit is being issued, what a customer has rented, and what has been returned. A desktop used at a service desk or equipment store should retain local working data during a network interruption.
RentIt+ separates local work from server confirmation. A desktop operation can be stored locally, but shared availability and concurrent changes still require server validation. Offline-first operation therefore introduces reconciliation and conflict handling; it does not guarantee that every local change will be accepted later.
| Area | Implemented responsibility |
|---|---|
| Catalog | Products, categories, pooled stock, and individually tracked units |
| Inventory | Location-specific balances, physical units, and inventory transactions |
| Customers | Customer records and management workflows |
| Orders | Preparation, order lines, assignment, and cancellation workflows |
| Rentals | Checkout, rental lines, and return workflows |
| Desktop | JavaFX interface, SQLite persistence, local changes, and HTTP synchronization |
| Web administration | Vue interface for catalog, customers, inventory, orders, rentals, devices, and operational views |
| Observability | HTTP and synchronization events, persisted history, and live SSE streams |
| Load Lab | Python scenario runner with a separate control API and interface |
| MCP | Private runtime with read-only operational tools callable from the administrator SPA and compatible MCP clients |
Load Lab and MCP support testing and operational analysis. Finance, maintenance planning, and advanced scheduling are outside the completed project scope.
The observability box represents backend event handling and streaming. The separate MCP runtime extends access to operational data through read-only tools.
The backend is organized as a modular monolith with domain, application, and adapter modules. The desktop has its own local models and persistence layer, while shared libraries define common domain types and synchronization messages.
The JavaFX client keeps a local working store and synchronizes with the backend.
- Guided project tour: the operational story and suggested review paths.
- Architecture and module boundaries: runtime responsibilities and design tradeoffs.
- Domain model and workflows: inventory, preparation, checkout, and returns.
- Offline synchronization: local identity, acknowledgements, canonical data, and conflicts.
- Observability and MCP: visual operational views and read-only tools.
- Testing and Load Lab: test layers, workflow scenarios, and concurrency checks.
- Desktop installation and upgrades: setup, checksums, and migration behavior.
- Illustrative protocol samples: small synthetic JSON examples.
The technical articles describe the implementation associated with desktop release v1.2.3, including its design tradeoffs and operational limits.
| Area | Technologies |
|---|---|
| Backend | Java 21, Spring Boot, Spring Web, Spring Security, JPA/Hibernate |
| Server persistence | PostgreSQL, Flyway |
| Desktop | JavaFX, SQLite, Java HTTP client |
| Web | Vue 3, Vite, Pinia, Vue Router |
| Testing and lab | JUnit, Mockito, AssertJ, Testcontainers, Python scenarios, FastAPI |
| Delivery | Gradle, Docker Compose, GitHub Actions, jpackage |
| Hosting | AWS EC2, Caddy, Cloudflare; Cloudflare Pages for the SPA |
The web SPA and desktop client use the API at https://rentitapi.brianronock.com. Account access is separate from downloading an installer.
Treat the shared demo as a demonstration environment. The auditor role supports selected order and desktop rental workflows, so it is not a strictly read-only account. Use only fictional data and avoid changing other visitors' records. For an initial review, start with the documentation and browse existing data.
README.md
docs/ Architecture, workflows, sync, operational tools, and installation
samples/ Synthetic synchronization payloads with explanations
screenshots/ Desktop, web, synchronization, Load Lab, and MCP views
diagrams/ System, workflow, persistence, and module illustrations
Installers are available through GitHub Releases. The protocol samples use fictional data to explain the message formats. Application source and deployment configuration remain in the private repository.
Brian Rono and Babak Nourbakhsh
HTL diploma project in software engineering.
This repository is provided for portfolio review and educational reference. The contents are all rights reserved; no open-source license has been granted. Third-party software bundled with desktop installers is subject to its respective license terms.