About the role

We are looking for a Senior Fullstack Engineer to join Proxet and contribute to a long-term engagement with a UK-based technology company developing simulation and decision-support solutions for governments and enterprises.

Who are we looking for?
Skills & Experience:
7 + years of professional software engineering experience, with strong expertise in frontend development and hands-on backend experience.
Strong knowledge of React and JavaScript, including component design, hooks, state management, routing, and asynchronous data handling.
Experience building maintainable frontend architectures and reusable UI components.
Solid knowledge of HTML and CSS, including responsive layouts and accessible interfaces.
Hands-on experience developing Python backend services, application logic, and APIs.
Experience integrating frontend applications with REST APIs, including authentication, validation, loading states, and error handling.
Experience with relational databases, preferably PostgreSQL, including data modelling and query optimisation.
Understanding of microservices, distributed systems, and the interaction between applications and backend services.
Practical experience deploying and troubleshooting containerised applications using Docker and Kubernetes.
Experience with CI/CD pipelines, Git workflows, and automated testing across frontend and backend components.
Strong debugging skills and the ability to investigate issues across the application stack.
Experience using AI coding assistants in development, with the ability to review, validate, and take responsibility for generated code.
Experience communicating directly with customers or external stakeholders to clarify requirements and discuss technical solutions.
Ability to explain technical concepts to non-technical audiences and translate operational needs into application features.
Strong ownership, pragmatic technical judgement, and comfort working with evolving requirements.
Understanding of the Ukrainian context and confidence in communicating with local organisations.
Professional proficiency in Ukrainian and English for customer meetings, technical discussions, and written communication.
Willingness and ability to travel to customer sites within Ukraine.

Nice to have
Experience with mapping and geospatial visualisation tools such as Mapbox or deck.gl.
Experience building interfaces for analytical workflows, complex datasets, or simulation results.
Familiarity with Redux, RxJS, Vite, or similar frontend libraries and tooling.
Experience with Node.js and frameworks such as Express or NestJS for work across broader platform tooling.
Experience with Kafka, Dagster, or other messaging and data-processing technologies.
Familiarity with gRPC, document databases, and object storage.
Experience with GCP, AWS, Azure, or private-cloud deployments.
Familiarity with Helm or OpenShift.
Experience integrating AI agents, MCP interfaces, or LLM APIs.
Experience working with public-sector organisations, local authorities, or infrastructure operators.
Familiarity with simulation platforms, digital twins, or decision-support systems.

Responsibilities

Design, develop, and maintain fullstack applications, with a primary focus on React interfaces and supporting Python backend services.
Build user workflows for configuring scenarios, interacting with platform capabilities, and exploring simulation results.
Develop reusable UI components and client-side integration layers that simplify access to platform services.
Implement backend logic, APIs, and data integrations required by the application.
Work directly with customers and external organisations in Ukraine to understand their processes, needs, and operational constraints.
Participate in customer meetings and on-site visits, demonstrate functionality, gather feedback, and clarify technical options.
Translate customer needs into application features and deliver them from implementation through testing and deployment.
Adapt existing platform capabilities to local use cases and share relevant feedback with engineering and product teams.
Integrate applications with customer data, backend services, and containerised simulation capabilities.
Work with PostgreSQL and collaborate with backend engineers on data access and processing workflows.
Improve frontend performance, API interactions, and application reliability.
Write and maintain automated tests across frontend and backend functionality.
Contribute to CI/CD workflows and deployment of containerised applications in Kubernetes-based environments.
Troubleshoot issues across the UI, APIs, data integrations, and deployment environment.
Collaborate with backend engineers, platform specialists, modellers, and delivery stakeholders.
Participate in code reviews and technical design discussions, documenting important decisions.
Use AI development tools effectively while maintaining code quality, correctness, and maintainability.