Middle FullStack Developer

RAYTON is a leading Ukrainian energy engineering group specializing in commercial solar power plants and Battery Energy Storage Systems (BESS). We design and deliver turnkey energy solutions that help businesses achieve energy independence across Ukraine, Europe, the United States, and the Middle East.
With over 2,500 completed projects, RAYTON has established a strong track record of delivering energy solutions for major companies, including OKKO, KyivGuma, and Velmart, using Tier-1 equipment.
As we continue to expand our energy solutions and energy storage business, we are looking for a Full-Stack Developer (Middle Strong) to join our team and contribute to the development of software solutions supporting our technical and business operations.
About the Role
Mandatory
Proven commercial experience working in a manufacturing or industrial company is required. Candidates must have practical experience in a production environment, ideally involving industrial equipment, manufacturing processes, equipment monitoring, or production data analytics
We are developing an internal web platform for real-time monitoring and data analytics, with IoT integrations and a high volume of time-series data.
This is an engineering-oriented role: most of the work involves calculations, data processing and equipment configuration logic rather than typical CRUD or e-commerce features.
Key Responsibilities
— Develop and maintain backend services and APIs using Python and FastAPI (async).
— Implement calculation and optimization logic based on technical specifications with formulas, constraints and acceptance test cases.
— Process and validate time-series data from equipment (gaps, duplicates, units, time zones).
— Develop configuration and settings management for equipment parameters, with validation and audit trail.
— Build and improve frontend applications using React and TypeScript, including dashboards and time-series charts.
— Work with relational databases: data modeling, query optimization on large tables, and schema migrations.
— Implement real-time features using MQTT and WebSockets.
— Verify calculation results against reference data and cover them with regression tests.
— Work closely with engineers to translate technical requirements into reliable code.
Preference will be given to candidates with experience in Industrial IoT, SCADA/monitoring systems or industrial automation.
Requirements
3+ years of commercial experience with Python; solid experience with FastAPI.
— Experience implementing calculation-heavy or algorithmic business logic (not only CRUD).
— Ability to read technical specifications with formulas and turn them into tested code.
— Attention to numerical correctness: units of measurement, rounding, precision, edge cases.
— Strong SQL skills and practical experience with SQLAlchemy; MySQL/MariaDB preferred.
— Experience optimizing queries on large datasets (tens of millions of rows).
— Experience processing and validating time-series data.
— Experience handling dates and time zones correctly (UTC storage, local time display, daylight saving time transitions).
— 2+ years of experience with React and TypeScript.
— Experience with Docker and Linux environments.
— Knowledge of MQTT and WebSockets.
— Responsible approach to production systems: safe migrations, environment separation, secrets management.
— Good English for technical documentation and code.
— Strong problem-solving skills and ability to work independently.