Software Engineer
Summary
Flix seeks a senior Java/Kotlin engineer on a B2B freelance contract in Poland to maintain and evolve a product that coordinates Flix with Mobility Partners, keeping millions of passengers moving. Day-to-day work spans distributed systems (Spring Boot, Kafka, MySQL/Postgres, Redis, MongoDB, S3), architectural decisions, and AI-assisted development.
Rate: 135 – 170 PLN/hour (B2B)
We are looking for an experienced Software Engineer to join Flix on a freelance/service agreement basis (B2B contract). The team owns a critical product at the heart of the Flix ecosystem - optimizing how Flix coordinates with Mobility Partners to keep millions of passengers moving across the globe.
Scope of Services
You'll have a real impact, contributing not just to code, but to product and technical decisions that directly impact the business. With your services you’ll maintain and continuously evolve a mature, stable product while simultaneously pushing it forward - tackling complex architectural challenges, reducing manual processes, and exploring AI-driven solutions.
About the Engagement
- You’ll collaborate with a distributed, self-organized, cross-functional team
- You’ll have the opportunity to co-design new products from the ground up while continuously improving existing ones, with room to explore and implement cutting-edge technologies
- Drive the development process in an Agile environment, placing Flix users at the center of each solution you and the team create
- Support technical decisions across teams, improving technical excellence through collaboration and lateral leadership
- Help define and deliver products that optimize the coordination between Flix and Mobility Partners, enhancing efficiency and reducing manual tasks
About You
- 6+ years of experience as a Software Java and/or Kotlin Engineer, with knowledge of distributed systems, including Spring/Spring Boot, Kafka, MySQL/Postgres, Redis, MongoDB and S3
- Willingness to work with both Java (for existing products) and Kotlin (for new ones)
- Experience in making architectural decisions, and writing clean, performant, well-tested code
- Autonomy and ownership in solving technical challenges, as well as strong communication skills when working with a distributed team
- A strong product mindset, with a passion for user experience and a data-driven approach to decision-making
- Experience in coding with AI
- Fluent in English (upper-intermediate or higher)
Nice-to-Haves
- Experience with DevOps and infrastructure: Kubernetes, Docker, Gitlab CI, AWS, Terraform
- Familiarity with data engineering (ETL, Snowflake)
- Ability to be a sparring partner, share knowledge and experience, explain complex things in plain language, consult/mentor, and provide constructive feedback
Cooperation Model
- Cooperation based on a service agreement (B2B/freelance contract), not an employment contract
- You will operate as an independent contractor, responsible for delivering agreed services and submitting invoices
- Location: open for contractors based in Poland
Skills
As published by greenhouse · 5 questions
Basics
First Name, Last Name, Email, Phone, Resume/CV
Short answers (2)
- Salary expectations: employment contract = gross per annum; B2B = net hourly rate
- Where are you currently located? City and country
Pick from a list (3)
- Contract preference: Umowa o Pracę / employment contract or B2B contract?
- Do you require visa/residence sponsorship to be employed in Poland?
- Do you already have a registered business entity in Poland, or are you able to set one up?