Senior Software Engineer - JVM, Kotlin

Simple Machines; Kraków; Hybrid; PLN 160,000 - 240,000; Full time

Benefits offered by this job

Health and Wellbeing Allowance

Professional Development Budget

Certification Budget

Equipment Allowance

Job summary

Simple Machines is looking for a Senior / Lead Full Stack Engineer in Kraków, Poland. You will collaborate with teams to develop scalable solutions across the tech stack, from front-end to back-end and data pipelines.

The role requires strong programming skills, expertise in APIs, and familiarity with cloud infrastructure. The company offers a competitive salary and various professional development benefits, including health allowances, training budgets, and equipment allowances.

Qualifications

• Strong written and verbal English skills are required.
• Core foundation in programming, especially in JVM languages, is essential.
• Experience designing and implementing data-driven APIs is needed.

Responsibilities

• Design backend services for a scalable marketing platform.
• Document technical requirements and deliverables.
• Ensure delivery and support for developed solutions.

Skills

English proficiency

Programming in JVM languages (Kotlin or Java)

API design

Frontend development (React.js, Tailwind, Redux, Typescript)

Cloud infrastructure experience (AWS, Google Cloud, Azure)

Infrastructure-as-code (Terraform, CloudFormation)

SQL databases

Unit and integration testing

Tools

Docker

Kubernetes

Job description

Simple Machines is a leading independent boutique technology firm with a global presence, including teams in London, Sydney, San Francisco, and New Zealand. We specialise in creating technology solutions at the intersection of data, AI, data engineering, and software engineering.

We design and build bespoke data platforms and unique software products, create and deploy intelligent systems, and bring engineering expertise to life by transforming data into actionable insights and tangible outcomes.

We engineer data to life.

As we scale our EMEA Engineering Operations, this role will partner closely with our UK leadership team and focus on supporting our UK-based clients. While you'll enjoy the flexibility of working remotely, you'll be closely aligned with our UK delivery teams and client stakeholders, ensuring time‑zone overlap and easier collaboration.

Location and Eligibility

Must be based in Poland with citizenship or full‑time working rights to be considered for this opportunity.

The Role

As a Senior / Lead Full Stack Engineer at Simple Machines, you'll be at the heart of groundbreaking projects, collaborating closely with both our talented internal team and forward‑thinking clients. In this hands‑on role, you'll drive the development of sophisticated, scalable solutions across the full technology stack—from intuitive frontends and robust backends to powerful data pipelines and resilient infrastructure. If you're passionate about solving complex problems and pushing the boundaries of what's possible, this role offers the perfect platform for you to make a real impact.

Key Responsibilities

• Design and technically develop backend services for a highly scalable marketing platform.
• Design APIs, applications, and infrastructure; document technical requirements and design for the client.
• Ensure end‑to‑end delivery and support, including build, automation, deployment, and operations for everything that is developed.
• Partner with client stakeholders and team members to gather business requirements, collaborate on design decisions, and translate them into technical and design requirements.
• Operate within an iterative delivery team using Agile delivery tools and practices.
• Collaborate remotely and in‑person with the delivery team and client stakeholders.

Skills & Experience

• Strong written and verbal English.
• A consultative approach to software development and software engineering.
• Core foundation in programming, especially in JVM languages (particularly Kotlin or Java).
• Experience designing and implementing data‑driven APIs.
• Exposure to frontend development (particularly React.js, Tailwind, Redux, Typescript).
• Past project experience with large‑scale web services.
• Cloud infrastructure experience with AWS and/or Google Cloud, Azure, etc.
• Infrastructure‑as‑code experience, such as with Terraform or CloudFormation.
• In‑depth experience with unit and integration testing, and test automation generally. Ideally TDD and/or BDD.
• Experience working with SQL databases in the context of implementing data‑driven APIs, and designing database schemas and queries to meet business requirements.

Nice to Have

• A passion and proven background in picking up and adopting new technologies on the fly.
• Exposure to Scala or functional programming generally.
• Exposure to NoSQL databases such as DynamoDB, Cassandra, HBase, Bigtable, or Cosmos DB.
• Experience with Git workflows and the ability to tailor the workflow to project needs.
• Experience with containerised application deployment using Docker, Amazon ECS, Kubernetes, etc.

Benefits in Poland

• Competitive salary and benefits package.
• Join a fast‑growing team – 30% growth in the last 12 months.
• Health and Wellbeing Allowance: 6,129 zł per year to be used for food and non‑alcoholic beverages during business hours, healthcare, gym memberships, sporting goods and accessories, and any wellness appointments.
• Professional Development: 7,355 zł annual budget for training, courses, and conferences, with potential for additional funding.
• Certifications: 12,259 zł annual budget for certifications and related courses.
• Equipment Allowance: 6,129 zł for Poland team members, plus Apple MacBook Pro laptops and necessary accessories.