Senior Staff Software Engineer at kontakt – Kraków | Jobyssey

About

Inside health systems, where every second can matter, operations are still spread across dozens of disconnected tools and platforms. is changing that.

We combine proprietary hardware, AI-powered intelligence, and deep integrations with the technology health systems already have in place to build real-time understanding of what's happening across their operations. That intelligence becomes the execution layer care teams have been missing, helping them make smarter decisions and deliver better patient care.

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, we’ve more than doubled our revenue and are rapidly scaling with a clear path toward $100M in annual recurring revenue.

If you're excited to solve hard problems and help health systems deliver better care, we'd love to meet you!

is the leading IoT platform for real-time location and telemetry in healthcare and enterprise. Our 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 team is the connective tissue of this platform. We own the full data ingress pipeline — from third-party devices (Cisco, Aruba, and beyond) to our internal Kafka backbone — and we own egress: streaming enriched location and telemetry data out to downstream systems, external APIs, and partner platforms. We are rebuilding this domain the right way: event-driven, observable, documented, and built to scale.

We need a technical anchor — someone senior enough to raise the bar, pragmatic enough to ship, and confident enough to drive alignment across engineering and product.

What you will work on:

Data ingress & device integration

Own the pipeline that brings external device data into the platform. Build and maintain robust integrations with Cisco Spaces, Aruba, and similar third-party infrastructure. High-volume BLE telemetry, Kafka Streams, gRPC — multi-tenant SaaS where both 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 — real-time position feeds, alarm forwarding, standards-compliant adapters. You own how the outside world consumes data.

Architecture & technical leadership

You will drive the architectural evolution: what to rewrite, what to stabilize, and how to sequence it without breaking production. You establish the engineering standards — documentation, testing with Testcontainers, observability with Prometheus/Grafana — and you hold the team to them.

Cross-team ownership

Work directly with product stakeholders to translate business requirements into engineering decisions. When scope is unclear, you clarify it. When dependencies block the team, you resolve them.

Day-to-day Reponsibilities:

Design, build, and maintain Java/Spring 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 — the team currently operates on verbal agreements; you will change that
Use AI tools as a core part of your development workflow: code generation, debugging, documentation, prototype acceleration
Define and enforce testing standards using Testcontainers and CI pipelines (Jenkins, GitHub Actions)
Instrument services with Prometheus and Micrometer; build Grafana dashboards that give the team real operational visibility
Collaborate with Data Platform and SRE teams on Kafka topology, state store configuration, and infrastructure ownership
Mentor engineers on the team — through code reviews, design sessions, and honest feedback

What we are looking for:

7+ years of backend software engineering, with strong production Java experience — Spring Boot and ideally Kotlin too
Deep, hands-on Apache Kafka knowledge: Streams, state stores, topology design, and operational behavior — not just produce/consume
Experience building real-time, event-driven distributed systems in multi-tenant SaaS environments
Solid database fluency: MongoDB, PostgreSQL, Redis — you know when to use what and why
Hands-on AWS experience: EKS, Kinesis, S3; comfortable reading and writing Terraform and Helm
Track record of taking ownership of a messy, under-documented domain and making it better
Ability to work directly with product and business stakeholders — you can translate between engineering and everything else
Clear written and verbal English; the team is international
Based in or willing to relocate to Kraków, Poland

Nice to have:

Experience with IoT or BLE telemetry systems
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

The kind of Engineer we are hiring:

You should be comfortable with ambiguity, allergic to sloppiness, and capable of holding a high bar while still shipping. If you think AI tools are optional extras rather than a core part of how modern engineers work, this is not the right role.

We Offer:

Competitive salary reflecting staff-level seniority — we benchmark against market

Equity in a Series C company with a clear growth trajectory

Private healthcare, Multisport card, and standard benefits package

Hybrid from Kraków office - at least 2 days in the office

A real technical challenge — not a maintenance role on a stable codebase

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