Senior Staff Software Engineer

Kontakt.io is the leading IoT platform for real-time location and telemetry in healthcare and enterprise. Their systems monitor hundreds of thousands of assets and people across hospitals and campuses globally, processing billions of BLE events daily through a Kafka-first, cloud-native architecture. The company is backed by Goldman Sachs and trusted by leading health systems including HCA Healthcare, Sutter Health, AdventHealth, Trinity Health, Northwell Health, Cleveland Clinic, and the U.S. Department of Veterans Affairs. They have more than doubled revenue over the past year and are on track to surpass $70M in annual recurring revenue.

• 7+ years of backend software engineering.
• Strong production experience in Java and Spring Boot, with experience in Kotlin.
• Deep, hands-on knowledge of Apache Kafka 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 experience with AWS services including EKS, Kinesis, and S3.
• Comfortable reading and writing Terraform and Helm.
• Ability to take ownership of a messy, under-documented domain and improve it.
• Ability to work directly with product and business stakeholders to translate requirements.
• Clear written and verbal English at C1 level.
• 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.

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.

Architecture & technical leadership:

• Drive architectural evolution including what to rewrite, stabilize, and sequence without breaking production.
• Establish engineering standards including documentation, testing with Testcontainers, and observability with Prometheus/Grafana.

Cross-team ownership:

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

Day-to-day Responsibilities:

• Design, build, and maintain Java/Spring Boot and Kafka Streams-based services processing real-time BLE and IoT telemetry at scale.
• Own ingress integrations with third-party location platforms from protocol understanding to production reliability.
• Build egress pipelines streaming location and event data to downstream systems via REST, gRPC, and WebSocket.
• Drive architectural decisions and document them.
• Use AI tools as part of development workflow: code generation, debugging, documentation, and prototype acceleration.
• Define and enforce testing standards using Testcontainers and CI pipelines (Jenkins, GitHub Actions).
• Instrument services with Prometheus and Micrometer; build Grafana dashboards for operational visibility.
• Collaborate with Data Platform and SRE teams on Kafka topology, state store configuration, and infrastructure ownership.
• Mentor engineers through code reviews, design sessions, and honest feedback.

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