Software Engineer III (JS/TS)

TL;DR

Software Engineer III (JS/TS): Building tools and workflows for managing advertising transactions in a high-scale ad exchange with an accent on high-quality React user interfaces and Python APIs. Focus on end-to-end feature ownership, translating business rules into intuitive experiences, and ensuring reliability at massive scale.

Location: Krakow (remote work option)

Salary: Employment contract (17 708 - 19 792 PLN gross/monthly) OR B2B (147 - 164 PLN net/hourly)

Company

Digital advertising technology company operating a high-scale ad exchange handling billions of ad requests daily across global markets.

What you will do

• Design and build maintainable user interfaces using TypeScript and React.
• Develop Python-based backend APIs supporting frontend workflows.
• Translate business rules and data dependencies into intuitive UIs and reliable integrations.
• Own features end-to-end from design through rollout and operations.
• Write automated tests for frontend and APIs.
• Collaborate with Product, UX, QA, and Engineering teams.
• Improve usability, reliability, and maintainability of systems.
• Contribute to technical direction and code quality.

Requirements

• Communicative Polish and English languages
• 4+ years of professional software engineering experience.
• Experience building web applications with JavaScript or TypeScript.
• Hands-on experience with React and modern frontend architecture.
• Understanding of component-based development, state management, API integration, and frontend performance.
• Experience designing REST APIs or backend services, preferably in Python.
• Practical understanding of databases and backend data flows.
• Commitment to software quality with automated tests.

Nice to have

• Experience with advertising technology, digital media, or marketplace platforms.
• Experience with GraphQL.
• Experience with cloud platforms like GCP, AWS, or Azure.

Culture & Benefits

• Flexible working hours and remote work option.
• Annual performance bonus and holiday allowance.
• Private health care, life and travel insurance for you and family.
• Training access to LinkedIn Learning and tech workshops.
• MultiKafeteria program, pension scheme (PPK), additional paid day off.
• Monthly work-from-home allowance and home office setup payment.
• Peer recognition platform and celebration of personal milestones.