Database Engineer

About the company

XTB is a global company from the financial industry, focusing on online trading of financial instruments. We are the largest FinTech in Poland and a leader in Central and Eastern Europe, and the range of our operations covers several countries, including Asia and South America. At XTB, we focus on the development of our employees, giving them opportunities to gain knowledge and skills in various fields, as well as offering a number of training and development programs. If you are looking for challenges and want to gain valuable experience in an international business environment, XTB is the right place for you.

We are a certified Great Place to Work company.

Your tasks

We are looking for an experienced Database Administrator (DBA) to take ownership of our mission-critical database infrastructure. In this role, you will manage, scale, and optimize high-availability PostgreSQL clusters and distributed MongoDB sharded environments, ensuring data integrity, peak performance, and enterprise-grade resilience.

• Administering, configuring, and maintaining production PostgreSQL clusters, including streaming replication, connection pooling, and high-availability setups.
• Managing distributed MongoDB environments: designing and optimizing sharded clusters, replica sets, and query routing (mongos).
• Deep performance tuning and capacity planning: identifying bottlenecks, optimizing slow queries, indexing strategies, engine configuration, and OS-level storage I/O parameters.
• Designing, maintaining, and automating end-to-end backup and recovery strategies (including Point-in-Time Recovery - PITR) for both relational and document stores.
• Planning and executing regular Business Continuity Planning (BCP) and Disaster Recovery (DR) drills, failover testing, and data restoration drills.
• Administering databases at the Linux level (Debian/Ubuntu): kernel tuning, memory allocation, storage diagnostics, and system hardening.
• Automating database maintenance, monitoring, deployments, and routine DBA tasks using Ansible, Python, and Bash.
• Participating in a structured on-call rotation to guarantee 24/7 availability and rapid response for mission-critical database incidents.
• Performing occasional on-site visits to data centers in Poland and across Europe for infrastructure rollouts, recovery tests, or deep diagnostic operations.
• Collaborating with development, platform, and security teams on data modeling, schema changes, and compliance.

Requirements

• 4+ years of hands-on experience as a Database Administrator managing enterprise-scale production environments.
• In-depth practical knowledge of PostgreSQL: master-replica architectures, failover mechanisms (e.g., Patroni), logical/physical replication, and deep performance diagnostics (EXPLAIN plans, pg_stat_statements).
• Hands-on experience with MongoDB in distributed environments: sharding architecture, shard balancing, replica set election mechanics, aggregation pipeline tuning, and wiredTiger engine optimizations.
• Proven expertise in enterprise backup & recovery architectures.
• Strong Linux systems administration background (performance troubleshooting, storage/IOPS analysis, memory management, networking).
• Experience with modern database observability platforms (e.g., Prometheus, Grafana, Zabbix).
• Practical experience with DR and BCP frameworks, including automated failovers and real-world recovery exercises.
• Solid scripting and automation skills: Bash, Python, Ansible, and Git.
• Willingness to participate in paid on-call rotations and occasional travel to data centers.
• Polish proficiency sufficient for fluent communication.
• Technical English proficiency enabling fluent cross-team communication (min. B2 level).

Nice to Have

• Previous MS SQL and MySQL experience.
• Familiarity with Kubernetes database operators.
• Experience with Terraform or Infrastructure-as-Code workflows for DB provisioning.
• Knowledge of database security, compliance, and auditing standards (data encryption at rest/in transit, TLS, NIS2, GDPR).
• Relevant certifications (e.g., PostgreSQL Certified Professional, MongoDB Certified DBA).

Must have:

• PostgreSQL
• MongoDB
• Prometheus
• Grafana
• Zabbix
• Bash script
• Python
• Ansible
• Git