Experienced Software Engineer - Fulfillment Order Management

About the role

Customer Order Services (COS) is the strategic backbone for customer order data and processing at MediaMarktSaturn. It consolidates order information, standardizes access through a common API model, and orchestrates fine-grained workflows that power the end-to-end online order journey. Positioned as the main communication layer, COS connects the Order Management Systems (OMS) with major corporate applications - such as SAP Retail, Checkout, Payment systems, Invoicing applications, and Pick-and-Pack solutions - ensuring consistent, real-time order processing across the enterprise.

What you'll do

• Design, implement, and evolve COS REST APIs and event schemas (OpenAPI, API Gateway), enabling contract-first integrations and decoupling consumers from Order Management platform.
• Develop and orchestrate event-driven order workflows with Kafka/Kafka Streams and Temporal (basket-to-order, payment/checkout, digital activation, fulfillment, transport management), ensuring reliability, idem-potency, and auditability.
• Build and maintain data persistence and propagation: model order data in Protobuf, MongoDB, PostgreSQL, drive real-time synchronization to corporate systems, and support analytics via Pub/Sub to BigQuery with strong data quality and PII safeguards.
• Operate the platform on GCP/Kubernetes using GitOps (Flux): monitor and troubleshoot production, optimize performance and scalability, manage incidents, and continually improve SLAs, security, and resilience.

What we're looking for

• Strong experience building event-driven, distributed systems
• Proven track record designing contract-first RESTful APIs with OpenAPI, including versioning, error models, and API gateway policies (e.g., Kong/Apigee).
• Practical experience with relational and noSQL databases (like MongoDB and PostgreSQL), schema design, transactions, performance tuning in high-throughput environments.
• Experience in cloud-native operations, e.g. on GCP with Kubernetes and Terraform; GitOps (Flux), CI/CD, observability (logging, metrics, tracing), and production troubleshooting.
• Integration expertise using synchronous and asynchronous patterns (Kafka, Google Pub/Sub, etc.) across enterprise systems
• Strong focus on reliability, security, and compliance for customer order data (SLAs, auditability, PII/GDPR), with clear communication and cross-functional collaboration skills.

Nice to have

• Proficiency in Kotlin on the JVM; solid Java skills; familiarity with Python or TypeScript is a plus.

What you'll get

• Young environment, where not everything is written in stone, and where you are expected to contribute and co-create the culture of the Tech Hub and international collaboration model