Senior Staff Software Engineer

Kontakt Micro-Location Sp. Z.o.o.; Kraków; On-site; PLN 180,000 - 260,000; Full time

Benefits offered by this job

Equity

Private healthcare

Hybrid from Kraków office

Technical challenge

Growth opportunities

Job summary

Kontakt.io is seeking a senior backend engineer to own data integrations and real-time processing in a multi-tenant SaaS environment. You will build and scale Java/Spring Boot services with Kafka Streams, ensuring latency and correctness in hospital-focused workflows.

Collaborate with product and data teams, drive architectural decisions, and strengthen testing with Testcontainers, observability with Prometheus/Grafana, and robust ingress/egress pipelines. Based in Kraków with hybrid work.

Qualifications

• 7+ years of backend software engineering with Java and Spring Boot.
• Deep Apache Kafka knowledge and operational experience.
• Experience with real-time, event-driven distributed systems.
• Fluent English; Kraków resident or willing to relocate.
• Strong database fluency: MongoDB, PostgreSQL, Redis.

Responsibilities

• Own data integrations and real-time BLE/IoT telemetry processing at scale.
• Design and maintain Java/Spring and Kafka Streams services.
• Build ingresses with third-party location platforms and real-time data streams.
• Drive architecture decisions and implement testing and observability standards.
• Collaborate with Product and Data teams to translate requirements into engineering outcomes.
• Mentor engineers and uphold engineering excellence with Testcontainers, Prometheus, and Grafana.

Skills

Java/Spring Boot

Kafka Streams

AWS

Kotlin

PostgreSQL

Redis

Go

Tools

Prometheus

Grafana

Testcontainers

Kubernetes

Docker

Job description

We are makers and builders.
We challenge the status quo and have fun doing it.
We bring passion and purpose to making a difference in healthcare, elevating how care is delivered and experienced.

Every day, intelligent software orchestrates the physical world around us – from matching drivers with riders to optimizing global supply chains. Yet inside hospitals, where every second and every decision can affect a patient's life, operations are still spread across dozens of disconnected systems.

At Kontakt.io , we're changing that. By combining proprietary hardware, AI-powered intelligence, and deep integrations with the systems hospitals already rely on, we're creating a real-time understanding of hospital operations that software alone can't deliver. That intelligence powers the execution layer hospitals have been missing – helping care teams 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're pioneering the next generation of healthcare operations. We've more than doubled our revenue over the past year and are on track to surpass $70M in annual recurring revenue – not because we're following a market, but because we're defining one.

If you're excited to solve hard problems, work with a team of builders, and help hospitals deliver better care every day, we'd love to meet you!

Kontakt.io 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.

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:

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. 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 Kontakt.io 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

You are not like everybody else.
We are not like any other company.
We’d love to be part of your growth.