Senior Fullstack Software Engineer (Python/Java) - Service Agreement

Flix · Warsaw, Poland
Location
Warsaw, Poland
Type
Contract
Seniority
Senior
Salary
135–170 PLN / hour
Department
IT & Engineering
Posted
26 Oct 2026

Verified open 2 Nov 2026 · Source: Greenhouse

About the role

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). This is a contractor engagement for a seasoned professional with a full-stack mindset. 

Scope of Services

Developing Flix’s contact center applications, with a focus on scalable agent-facing interfaces and automation. The role will involve extensive discovery to identify the most efficient and effective workflows. 

Our tech stack

  • Languages & Frameworks: Python, JavaScript, TypeScript, Java, flask, FastAPI, Node.js, React, Spring Boot.  
  • Cloud Providers and IaC: AWS, Azure, Terraform, Serverless.  
  • Data Layer: Elasticsearch, Snowflake 
  • Streaming and Messaging Layer: Kafka. 
  • Observability: Datadog, Kibana. 

About the Engagement

  • Deliver solutions for a defined portfolio of products, contributing to business objectives. 
  • Design and develop user-focused solutions tailored to product requirements and user needs. 
  • Apply Agile methodologies to organize and execute the development process. 
  • Develop and enhance products using modern technology stacks. 
  • Make technical decisions within the scope of services provided, promoting technical excellence and consistency across solutions. 

About You

  • Minimum 5 years of professional experience in full-stack development, with a focus on architecture, system design, and legacy product migration. 
  • Extensive experience with Python and its ecosystem for the development of new products. 
  • Solid knowledge of Java for the maintenance and further development of existing products. 
  • Strong focus on quality assurance practices and technical standards throughout the product development lifecycle. 
  • Hands-on with automated testing and experience with different test runners. 
  • Comfortable with Agile methodologies in planning and executing development work. 

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

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