T-Hub - Data Engineer with Java

T-Mobile is a leader in the telecommunications industry offering opportunities to work with technologies such as 5G, IoT, and AI.

• Strong experience with Google Cloud Platform including Dataflow, BigQuery optimization (partitioning and clustering), Pub/Sub, Dataproc, Cloud Monitoring, and Logging.
• Good understanding of IAM, VPC fundamentals, and service accounts.
• Deep expertise in Apache Beam with advanced transformations, windowing, triggering, side inputs/outputs, state and timers for streaming.
• Experience optimizing resource sizing and performance on Dataflow including high-throughput and low-latency pipelines, custom IOs, and debugging.
• Strong experience with Apache Spark including join, shuffle, partitioning optimization, schema evolution handling, and metrics debugging.
• Familiarity with Apache Flink and ability to implement streaming pipelines.
• Knowledge of Docker and Kubernetes for job packaging in Spark and Flink environments.
• Advanced SQL skills with complex queries, performance tuning, and incremental data processing.
• Ability to define and enforce data quality checks and acceptance criteria.
• Hands-on experience with Airflow and maintaining complex DAGs.
• Proven ownership of production-grade data pipelines focused on reliability and scalability.
• Extensive proficiency in Java including concurrency, immutability, and performance profiling.
• Experience building reusable libraries and enforcing code quality, testing standards, and reviews.
• Strong system design and API design skills for performance-critical code.
• Experience designing and architecting batch and streaming data systems including technology selection and standards definition.
• Ability to provide technical leadership, drive engineering strategy, and ensure scalability, security, and cost-efficiency.
• Proven track record building platform components like libraries, templates, governance frameworks, and data quality solutions.
• Experience with CI/CD for data (GitHub Actions, Cloud Build) and infrastructure-as-code tools like Terraform.
• Minimum 6 years of data engineering experience with architectural leadership.
• Track record delivering large-scale data systems and influencing cross-team outcomes.
• Ability to set architectural direction, ensure compliance and security, and drive platform improvements.
• Willingness to travel at least four times per year.

• Design and implement batch and streaming pipelines using Beam, Spark, and Flink.
• Perform data transformation operations for analytics and downstream services.
• Optimize jobs for performance and cost, and implement robust testing and observability.
• Build and manage Airflow orchestration.
• Troubleshoot production issues, lead incident resolution, and drive root-cause fixes.
• Contribute to team standards, templates, and reusable libraries.
• Use Java and Apache Beam as main programming language and library for streaming pipelines.
• Design and ship new pipelines or major refactors with measurable latency and cost improvements.
• Cooperate closely with Data Engineering Lead for onboarding and codebase understanding.
• Introduce or improve testing and observability patterns adopted by the team.

The data controller is T-Mobile Polska S.A. based in Warsaw, ul. Marynarska 12. Personal data processing is governed by legal regulations with candidates holding rights to access, correction, deletion, restriction, objection, and data portability. Data will be processed for recruitment purposes and possibly for future recruitments upon consent. Consent can be withdrawn anytime. Data recipients include Rocket Jobs and other entities engaged for recruitment purposes.