Senior/Mid Data Platform Developer

Quick Facts

• Role: Data Platform Developer (Mid/Senior)

• Work model: Remote (1x per month on-site in Wrocław)

• Contract: B2B

• Pay: 145–160 PLN/hour

Description

You’ll join a banking Data Platform team to design, build, and maintain scalable, event-driven solutions. The platform is based on Apache Kafka ecosystem technologies (Kafka Connect, kSQL, Kafka Streams) together with Spring Boot, Quarkus, and GraalVM, integrating NoSQL and analytics such as MongoDB, GraphQL, and Apache Iceberg.

Responsibilities

• Develop event-driven prototypes using Apache Kafka, Kafka Connect, Kafka Streams, and kSQL

• Define and version data schemas (Avro, Protobuf, JSON Schema)

• Build Spring Boot microservices handling Kafka events (producer, consumer, stream processing)

• Create a GraphQL API layer using Quarkus and GraalVM to expose data from MongoDB

• Configure and develop Kafka Connect connectors for MongoDB, S3, Apache Iceberg, and other systems

• Implement automation for generating Kafka environment configurations

• Add observability: metrics, logging, and tracing for event flows

• Diagnose replication, latency, and processing issues; tune Kafka configuration

• Collaborate in an Agile team with data engineers, DevOps specialists, and analysts

Requirements

• Practical experience (~3 years) with Apache Kafka in production environments

• Knowledge of Kafka internals: brokers, topics, consumers, producers, logs, replication mechanisms

• Good knowledge of Kafka Streams and kSQL

• Ability to configure and develop Kafka Connect connectors

• Strong Java skills and knowledge of Spring (Boot, Cloud, Security, Data)

• Experience with MongoDB, including schema design and query optimization

• Knowledge of GraphQL and ability to implement services

• Basic knowledge of Apache Iceberg table formats and metadata management

• Experience with monitoring tools: Prometheus, Grafana, OpenTelemetry

• Security knowledge: TLS, SASL, ACL, and encryption of data

• Basic knowledge of Python

Benefits

• Remote work with monthly office presence in Wrocław

• B2B contract