Freelance Kotlin Developer (Fulltime)

Dirkzwager; Toruń; On-site; PLN 100,000 - 140,000; Full time

Benefits offered by this job

Competitive salary

Remote-friendly setup

Direct impact on global product

Interesting domain challenges

Job summary

Dirkzwager is looking for a skilled backend developer to join their team in Toruń, Poland. You will build and maintain microservices using Java or Kotlin and take full ownership of your services, working on architectures that impact global logistics.

The role offers a competitive salary and a remote-friendly environment, promoting output-driven work in a complex and dynamic domain.

Qualifications

• 5+ years of professional backend development in Java and/or Kotlin.
• Hands-on production experience with AWS (ECS, Lambda, S3, RDS or DynamoDB).
• Strong command of Docker and containerized deployments.

Responsibilities

• Design and build JVM-based microservices running on AWS.
• Collaborate on API design and infrastructure decisions.
• Instrument services with monitoring tools and ensure code quality.

Skills

Java

Kotlin

AWS

Docker

CI/CD

PostgreSQL

RabbitMQ

Tools

GitHub Actions

OpenTelemetry

Prometheus

Grafana

Job description

You’ll be a core member of a small, high-ownership engineering team building and evolving the distributed microservices backend that powers our app. You’ll work across a complex domain – route optimization, schedule ingestion, geo-routing, and carrier data – at real scale, on AWS.

This is not a role for someone who waits for specs to land in their inbox. You’ll take full ownership of services from design through production, make architectural decisions, and proactively identify and fix problems before they become incidents.

What you’ll work on

• Design, build, and maintain JVM‑based microservices (Java / Kotlin) running on AWS ECS, App Runner, and Lambda
• Work with a rich data layer: PostgreSQL, DynamoDB, RedShift, Redis, and S3
• Build and consume event‑driven integrations via RabbitMQ and SNS
• Collaborate on API design across REST (API Gateway) and BFF patterns
• Instrument services with OpenTelemetry, Tempo, Prometheus, and Grafana
• Ship via GitHub Actions CI/CD pipelines with Docker and ECR
• Work with external integrations including Auth0, GraphHopper, PostHog, and Sentry
• Participate in architecture decisions and technical direction – your opinion will carry weight

Job Description

• Work permit for Poland
• 5+ years of professional backend development in Java and/or Kotlin
• Solid understanding of distributed systems design, microservice patterns, and event‑driven architecture
• Hands‑on production experience with AWS (ECS, Lambda, S3, RDS or DynamoDB)
• Experience with relational databases (PostgreSQL) and NoSQL (DynamoDB or similar)
• Strong command of Docker and containerized deployments
• Experience with CI/CD pipelines – we use GitHub Actions
• Clean code as a practice, not a talking point – you write code that your colleagues can confidently extend
• Genuine ability to self‑direct: you can take a loosely defined problem, break it down, make decisions, and deliver

Strong plus

• Kotlin specifically (greenfield services are Kotlin‑first)
• Experience with message brokers (RabbitMQ, SQS/SNS)
• Familiarity with observability tooling (OpenTelemetry, Prometheus/Grafana stacks)
• Background in logistics, routing, geospatial, or supply chain domains
• Experience integrating third‑party APIs (auth providers, mapping/routing engines, analytics)

Qualifications

• Small team, high trust – no micromanagement, no approval chains for every decision
• GitHub‑centric workflow – PRs, reviews, and automated pipelines keep quality high without bureaucracy
• Observability‑first – we monitor, alert, and fix things before users notice
• Clean code culture – we refactor, we review, we don't let tech debt compound silently
• AWS‑native – we use managed services where they make sense and containers everywhere else

What we offer

• Competitive salary benchmarked to your market
• Remote‑friendly setup (we care about output, not location)
• Direct impact on a product used by global logistics professionals every day
• Work in a genuinely interesting domain – intermodal routing is hard, and the problems are real
• A lean, senior team where your architecture decisions actually ship