Senior Developer - Backend

The largest ICT employer in Hungary, Deutsche Telekom IT Solutions (formerly IT-Services Hungary, ITSH) is a subsidiary of the Deutsche Telekom Group. Established in 2006, the company provides a wide portfolio of IT and telecommunications services with more than 5000 employees. ITSH was awarded with the Best in Educational Cooperation prize by HIPA in 2019, acknowledged as one of the most attractive workplaces by PwC Hungary’s independent survey in 2021 and rewarded with the title of the Most Ethical Multinational Company in 2019. The company continuously develops its four sites in Budapest, Debrecen, Pécs and Szeged and is looking for skilled IT professionals to join its team.

Digital Construction Support (DCS, *Digitale Baubegleitung*) is the central platform supporting the digital
management and documentation of fiber construction sites in Germany. The platform helps construction supervisors and partners work more efficiently, improves quality during construction, and enables greater automation of documentation and billing processes.
You will join a cross-functional team responsible for developing and operating a distributed ecosystem of backend services and integrations.

Your responsibilities
- Own backend services throughout their lifecycle: design, implementation, testing, deployment, operation,  and continuous improvement.
- Translate product and business requirements into maintainable technical designs, clearly communicating risks and trade-offs to Product Owners, architects, and other engineering teams.
- Design and implement secure, versioned REST APIs and maintain their OpenAPI contracts.
- Develop primarily with Node.js and TypeScript, using PostgreSQL/PostGIS for relational and geospatial data.
- Design database schemas, transactions, indexes, and backward-compatible migrations; analyze and optimize complex SQL queries.
- Build reliable integrations with Kafka, AWS S3, GeoServer, and internal or external APIs.
- Implement automated unit and integration tests and contribute to API-contract, end-to-end, and performance testing.
- Build observability into services through structured logging, metrics, tracing, health checks, and actionable
  alerting.
- Diagnose defects and production incidents, participate in root-cause analysis, and implement preventive
  improvements.
- Contribute to CI/CD pipelines and operate containerized services on OpenShift/Kubernetes.
- Review merge requests, mentor engineers, and promote pragmatic engineering and quality standards.
- Maintain API documentation, architectural decisions, and operational runbooks.
- Use AI-assisted development tools responsibly, retaining full accountability for the correctness, security, privacy, and maintainability of delivered code.

Required experience
- Strong professional experience with Node.js and TypeScript, including asynchronous programming, production debugging, and type-safe application design.
- Strong SQL and PostgreSQL skills, including data modeling, transactions, indexing, query-plan analysis, and connection pooling.
- Experience designing and maintaining RESTful APIs and OpenAPI specifications.
- Experience with automated backend testing using Jest or Vitest and tools such as Supertest.
- Practical understanding of distributed systems and microservice design, including failure handling, idempotency, and backward-compatible interfaces.
- Experience with authentication, authorization, input validation, and secure backend development.
- Experience operating production services, including monitoring, troubleshooting, and incident analysis.
- Ability to lead technical discussions, communicate trade-offs, review code constructively, and mentor colleagues.
- Professional working proficiency in English.

Valuable additional experience
- PostGIS, GeoJSON, coordinate reference systems, or other geospatial technologies.
- Kafka and event-driven architecture.
- AWS S3 and secure object-storage patterns.
- Docker and OpenShift/Kubernetes.
- Knex.js or comparable SQL query and migration tooling.
- OpenTelemetry, Prometheus, Grafana, or structured logging platforms.
- NGINX and API gateway or reverse-proxy configuration.
- Python services or data-processing workflows.
- GitLab CI/CD, API linting, container security scanning, and automated release pipelines.

* Please be informed that our remote working possibility is only available within Hungary due to European taxation regulation.