Staff Software Engineer

Kontakt.io is a company working on a platform that integrates data from third-party devices such as Cisco and Aruba, focusing on real-time BLE and IoT telemetry at scale. The team owns the full data ingress pipeline and egress layer, building multi-tenant SaaS solutions with event-driven architecture.

• 7+ years of backend software engineering experience with strong production Java skills, including Spring Boot and ideally Kotlin.
• Deep, hands-on Apache Kafka knowledge including Streams, state stores, topology design, and operational behavior.
• Experience building real-time, event-driven distributed systems in multi-tenant SaaS environments.
• Solid database fluency with MongoDB, PostgreSQL, and Redis.
• Hands-on AWS experience with EKS, Kinesis, S3; comfortable with Terraform and Helm.
• Proven ability to take ownership of complex, under-documented domains.
• Ability to work directly with product and business stakeholders and translate between engineering and business.
• Clear written and verbal English skills.
• Based in or willing to relocate to Kraków, Poland.

Nice to have:

• Experience with IoT or BLE telemetry systems.
• Experience with Go or Python for tooling and automation.
• Familiarity with AsyncAPI, Drools rules engine, or OAuth2/Keycloak.
• Background in a high-growth Series B/C product company.

Data ingress & device integration:

• Own the pipeline that brings external device data into the Kontakt.io platform.
• Build and maintain robust integrations with Cisco Spaces, Aruba, and similar third-party infrastructure.
• Handle high-volume BLE telemetry, Kafka Streams, gRPC in a multi-tenant SaaS environment where correctness and latency matter.

Data egress & external integrations:

• Build and evolve the egress layer that streams enriched location and event data to partner systems and customer-facing APIs.
• Manage real-time position feeds, alarm forwarding, and standards-compliant adapters.
• Own how the outside world consumes Kontakt.io data.

Architecture & technical leadership:

• Drive architectural evolution including decisions on rewriting, stabilizing, and sequencing without breaking production.
• Establish engineering standards such as documentation, testing with Testcontainers, and observability with Prometheus/Grafana.
• Hold the team to these standards.

Cross-team ownership:

• Work directly with product stakeholders to translate business requirements into engineering decisions.
• Clarify unclear scope and resolve dependencies blocking the team.

Additional responsibilities:

• Design, build, and maintain Java/Spring and Kafka Streams-based services.
• Use AI tools as a core part of development workflow.
• Define and enforce testing standards using Testcontainers and CI pipelines (Jenkins, GitHub Actions).
• Instrument services with Prometheus and Micrometer; build Grafana dashboards.
• Collaborate with Data Platform and SRE teams on Kafka topology and infrastructure.
• Mentor engineers through code reviews, design sessions, and feedback.

Based in or willing to relocate to Kraków, Poland.