Senior/Staff Backend Engineer, Java, Kafka

Oscilar

full-time

Posted on: 9/3/2025

Location: 🇵🇱 Poland

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Senior

ApacheAWSCloudDistributed SystemsDynamoDBEC2GrafanaJavaKafkaPostgresPrometheusRedisTerraform

About the role

Shape the future of trust in the age of AI at Oscilar, building an AI Risk Decisioning Platform for banks, fintechs, and digital organizations.
Design, implement, and optimize backend services using Java and AWS technologies to handle high-throughput, real-time data streams.
Lead architecture, deployment, and optimization of Apache Kafka, including building and managing topics, brokers, producers, consumers, Kafka Streams, and Kafka Connect.
Scale and maintain databases such as Postgres, Redis, DynamoDB, and ClickHouse; optimize schemas, indexing, and partitioning.
Establish CI/CD pipelines, implement infrastructure security and performance monitoring, and ensure data integrity.
Collaborate across product, frontend, and data engineering teams; mentor junior engineers and conduct code reviews.

Backend Development: 8+ years of experience with Java in large-scale, distributed environments.
Kafka Mastery: Extensive experience with Apache Kafka, including Kafka Streams, Kafka Connect, partitioning, replication, and consumer group management.
Cloud Infrastructure: Strong experience with AWS services (e.g., MSK, EC2, RDS, DynamoDB, S3, Lambda).
Distributed Systems: Solid understanding of distributed system design, messaging patterns, and eventual consistency.
Performance Optimization: Proven ability to diagnose and resolve bottlenecks in streaming and database systems.
Nice-to-have: Experience integrating Kafka with analytics like ClickHouse; knowledge of CQRS and event sourcing; monitoring tools (Prometheus, Grafana); infrastructure automation (Terraform/CloudFormation); proficiency with Postgres, Redis, ClickHouse, DynamoDB; familiarity with encryption, RBAC, and secure API development.