We are looking for an experienced Backend Developer / Test Developer with strong Python skills to join the team and contribute to the development of a common web-based project layer for roadside measurement systems.

The goal of the stream is to develop a reusable HMI and API architecture that can serve multiple roadside products and measurement systems, with only minor adaptations and extensions required for different platforms.

The HMI will provide a modern, touch-friendly, web-based user interface with harmonized workflows and a recognizable design across products. The solution will be designed to support different application types and measurement systems while maintaining scalable client performance, including under bandwidth-constrained conditions.

The role has a strong focus on the backend/API layer and automated testing, ensuring reliable data flow from HMI interactions through the API Gateway and service layer to the backend services.

Key Responsibilities: Develop and maintain backend modules, utilities, and automated testing solutions using Python. Develop and maintain automated API and integration test suites covering application-layer endpoints. Test and validate GraphQL and RESTful/gRPC APIs, including schemas, queries, mutations, subscriptions, and service interactions. Verify end-to-end data flow from HMI user interactions through the API Gateway / Service Layer to backend services. Validate API contracts, data structures, and schema consistency across system components. Develop integration, regression, and contract tests to ensure reliable communication between HMI and backend services. Integrate automated tests into CI/CD pipelines, working closely with DevOps and development teams. Perform root-cause analysis of system failures at the protocol, logging, and container levels, rather than limiting investigations to UI-level issues. Work with embedded systems and target hardware lab environments, including via VPN or remote access. Investigate communication and integration issues involving ROS middleware, embedded systems, and roadside hardware. Work closely with Lead Frontend Developers to ensure reliable integration between the web-based HMI and backend services. Collaborate with DevOps to integrate API sanity checks, regression testing, and automated validation into Jenkins / GitLab CI pipelines. Support the development of a modular architecture that can be reused across multiple measurement systems with minimal adaptations. Contribute to troubleshooting and continuous improvement of the overall HMI/API solution.

Python & Backend Development Strong professional experience with Python. Experience developing backend modules, utilities, and automation frameworks. Good understanding of backend application architecture and service-based systems.

API & Communication Technologies Strong experience with GraphQL, including:Schemas Queries Mutations Subscriptions

Experience with RESTful and/or gRPC APIs. Understanding of API contracts, data structures, and service-to-service communication.

Automated Testing Strong experience with PyTest. Experience developing integration and API tests. Experience with contract testing and end-to-end testing. Experience integrating automated tests into CI/CD pipelines. Practical experience with GitLab CI and/or Jenkins.

Embedded & System Environment Working knowledge of ROS / Robot Operating System and middleware protocols used for communication with embedded/roadside hardware. Good understanding of Linux, including shell scripting and system troubleshooting. Experience working with Docker containers, particularly in embedded or constrained environments. Ability to troubleshoot issues across multiple system layers, including protocols, logs, containers, APIs, and backend services.

System & Architecture Understanding Ability to understand the system holistically from end to end Ability to analyze dependencies and data flows across different application layers. Understanding of modular and reusable software architectures.

Nice to Have Experience working with roadside systems, traffic management, or measurement systems. Experience interacting directly with physical target hardware in laboratory or development environments. Experience with ROS2 and related middleware. Experience with performance and reliability testing under bandwidth-constrained conditions. Experience working with web-based HMI systems or touch-friendly interfaces. Familiarity with frontend technologies and modern web application architecture. Experience with embedded Linux environments.