Python Backend Developer (FastAPI) — REST API Integration & Energy Savings

We're looking for an experienced Python backend developer to build the core integration layer of an energy optimization platform. The service connects three REST APIs, calculates daily energy savings, and exposes the results through a simple REST API for a dashboard. Frontend development is out of scope. Data Sources The middleware will integrate with three REST APIs: * Industrial IoT gateway – real-time power and energy consumption data . * Optimization engine – a third-party REST API that returns optimized consumption schedules and baseline consumption. * Electricity market API – public day-ahead electricity prices. What You'll Build The backend service will: * Poll and synchronize data from the three APIs. * Align data by time interval. * Calculate daily energy savings by comparing actual shifted consumption against a baseline. * Expose the calculated results through a clean REST API for a separate dashboard application. The calculation methodology has already been defined at a business level. We'll provide the required logic and expected outputs—the implementation is the scope of this project. Technical Stack * Python * FastAPI preferred (Flask is acceptable if you have a strong rationale) * REST API integrations * Dockerized application ready for deployment No frontend or machine learning work is required for this phase. Please structure your proposal with milestones so we can track progress against agreed deliverables. We're more interested in hiring the right developer rather than lowest bid. Ideal Candidate: * Has solid experience building Python backend services. * Is comfortable integrating third-party REST APIs from external documentation. * Writes clean, maintainable and well-tested code. * Enjoys building reliable first versions of products with a pragmatic, execution-focused mindset, balancing simplicity, reliability and maintainability. * Raises questions when requirements are unclear instead of making assumptions. * Can propose pragmatic technical solutions where appropriate. Experience with energy, utilities, IoT or industrial data is a plus, but not required. If you're interested, we'd love to hear about similar integration projects you've built and how you would approach this one.