🧭 Project Summary:
We are creating a unique, web-based platform that enables users to calculate the optimal size, configuration, and economic return of a photovoltaic (solar) system, optionally including battery storage. Based on location, consumption, and technical constraints, the platform generates a professional PDF report with:
- Energy autonomy simulations (50%, 80%, 95%)
- Cash flow and amortization calculations
- Climate-based production estimates
- Component suggestions with high-quality brands (Fronius, BYD, SunPower)
This is not just a simulator, but a tool tailored to real-world feasibility, using precise algorithms and real production data.
🤝 The developer will not work alone: direct technical support from the project owner is guaranteed throughout the development process, especially for understanding existing Python modules and business logic.
⚙️ Why this is Backend-Heavy:
Although the user interface is built on WordPress using Elementor (with simple forms and WooCommerce), most of the project complexity lies in the Python/Django backend, which is responsible for:
- Advanced energy modeling
- Irradiation and climate correction
- Battery sizing logic (based on dynamic autonomy targets)
- Incentive calculations and amortization simulation
- Multilingual, country-specific adaptation
- Generating accurate and branded PDF reports
- Generating electronic invoices in XML SDI format (Italian e-invoicing)
- Managing integration with Google APIs (Places, Elevation, Solar)
✅ Important: Several Python calculation modules are already written, with clear documentation and test inputs. The developer will reuse and structure this code into a coherent backend application.
🌍 Project Scope:
The platform is hosted at www.calcolofotovoltaico.it (Italian version). Future versions will target other countries (Germany, France, Spain, etc.).
This job focuses on completing the Italian version of the platform.
📌 Deliverables (First Phase – max 60 hours):
1. Refactor and integrate existing Python procedures into a modular Django backend
2. Create REST API endpoints to connect Django to the WordPress frontend
3. Handle form submissions from Elementor (via API, AJAX or hidden POST)
4. Generate branded PDF reports with charts, tables, and structured layout
5. Generate and deliver electronic invoices in XML SDI format for Italian customers
6. Connect Django backend with WooCommerce orders for triggering calculations and PDFs
7. Support localization structure to expand to other countries in the future
💻 Tech Stack:
- Frontend: WordPress (Elementor Pro, OceanWP theme), JavaScript (for API form handling)
- Backend: Python 3, Django, Django REST Framework
- PDF Generation: ReportLab, xhtml2pdf or similar
- APIs: Google Maps, Google Solar API, PVGIS (TBD), WooCommerce REST API
- Invoicing: XML SDI (Italy), multi-country VAT support (to be extended)
- Database: MySQL (already installed and configured)
🧠 Required Skills:
- Python (excellent level) and Django, including REST API development
- Experience integrating Django backends with WordPress frontends
- Advanced PDF generation in Python
- WooCommerce integration (webhooks, API, order metadata)
- Understanding of electronic invoicing logic (XML, VAT handling) is a plus
- Ability to read and structure existing code into scalable backend modules
- Familiarity with photovoltaic/energy systems is a bonus but not required
- Git, API authentication, MySQL
🧾 Documentation Provided:
- A full technical document detailing the backend structure, objectives, and logic
- JSON schemas for form validation
- Country-specific formulas for energy distribution
- Examples of existing Python functions
- Design mockups for the PDF output and invoice structure
- ✅ Direct support from the project owner will be available to clarify technical doubts, assist with logic comprehension, and guide the integration path if needed
📅 Timeline & Budget:
- Estimated effort: max 60 hours for the first phase (Italian version)
- Timeline: Deliverables ideally within 4 weeks
- Potential follow-up for international version (DE/FR/ES/GR/US...)
💬 Language:
English required. Some Italian understanding is a plus (technical terms and legal invoice fields may be in Italian).
💼 How to Apply:
Please include:
- A short description of your experience with Django and WordPress integration
- Relevant code samples or GitHub repositories
- Your timezone and availability
- Confirmation that you're comfortable working with existing Python code
- A rough estimate of the time you'd need for each deliverable
🔐 NDA & Confidentiality:
All code, technical documentation, business logic, and data shared during this project are strictly confidential. The selected developer must agree to the following terms:
- Do not share or reuse any part of the code, logic, or algorithms outside this project.
- Do not disclose any information about this project or its contents to third parties.
- Agree to sign an NDA if requested, before access to full documentation is granted.
- All deliverables will be considered "work for hire" and become the exclusive property of the client.
🎯 Goal:
Build a solid, reusable backend foundation that can be replicated across countries with minimal adjustments.