Senior Staff Software Engineer
Kontakt.io5 months ago
Kraków, PolandStaff+
Responsibilities
- Design, build, and maintain Java/Spring and Kafka Streams services processing real-time BLE and IoT telemetry at scale.
- Own integrations with Cisco Spaces, Aruba, and other third-party location platforms from protocol understanding through production reliability.
- Build egress pipelines delivering location and event data through REST, gRPC, and WebSocket interfaces.
- Drive architectural decisions, sequencing, documentation, and engineering standards for a currently under-documented domain.
- Use AI tools for code generation, debugging, documentation, and prototype acceleration.
- Define testing standards with Testcontainers and CI pipelines using Jenkins and GitHub Actions.
- Instrument services with Prometheus and Micrometer and create Grafana dashboards for operational visibility.
- Collaborate with Data Platform and SRE teams on Kafka topology, state stores, and infrastructure ownership.
- Mentor engineers through code reviews, design sessions, and feedback.
Requirements
- 7+ years of backend software engineering experience with strong production Java experience.
- Deep hands-on Apache Kafka expertise, including Streams, state stores, topology design, and operational behavior.
- Experience building real-time, event-driven distributed systems in multi-tenant SaaS environments.
- Fluency with MongoDB, PostgreSQL, and Redis and the ability to select appropriate databases.
- Hands-on AWS experience with EKS, Kinesis, and S3, plus comfort with Terraform and Helm.
- A track record of improving messy or under-documented technical domains.
- Ability to work directly with product and business stakeholders and translate business requirements into engineering decisions.
- Clear written and verbal English communication skills.
- Must be based in or willing to relocate to Kraków, Poland.
- Preferred qualifications include Kotlin, IoT or BLE telemetry experience, Go or Python for tooling and automation, AsyncAPI, Drools, OAuth2, Keycloak, and experience in a high-growth Series B/C product company.
Benefits
- Equity in a Series C company with a clear growth trajectory.
- Private healthcare, a Multisport card, and a standard benefits package.
- Hybrid work from the Kraków office with at least two days in the office.
- Competitive salary benchmarked against the market, with no specific base-pay amount stated.
- Opportunity to work on a significant real-time IoT platform and technical challenge rather than a maintenance codebase.
Tech Stack
Apache KafkaAWSGitHub ActionsGoGrafanagRPCHelmJavaJenkinsKotlinMongoDBPostgreSQLPrometheusPythonRedisSpring BootTerraform
Categories
About Kontakt.io
Kontakt.io builds Bluetooth Low Energy beacons, gateways, and an RTLS cloud platform used by hospitals and large facilities for asset tracking, staff safety, indoor navigation, and operational analytics. The company sells hardware integrated with SaaS subscriptions and APIs. Founded in 2013 and headquartered in New York, it is privately held and focuses on healthcare workflows and indoor journey analytics.