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 t