Openx

Software Engineer III ( JS/TS)

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Job Description

About the role

You will join the Core Exchange development team at OpenX. Our exchange handles billions of ad requests every day, connecting thousands of publishers with demand partners across the global advertising ecosystem. The platform runs in the cloud across multiple regions and operates at a scale where performance, reliability, correctness, and every millisecond matter.

The role focuses on building tools and workflows that help users manage advertising transactions. These tools help users configure business rules, review transaction setup, and keep platform behavior aligned with business agreements and financial processes.

This is a frontend-first engineering role with meaningful API ownership. Most of your work will focus on building high-quality user interfaces in TypeScript, primarily with React, while also contributing to Python-based APIs that support the product experience end-to-end. In practice, we expect the work to be roughly two-thirds frontend development and one-third API/backend development.

Prior AdTech experience is helpful, but not required.

Team setup

You will join a cross-functional product engineering team with a dedicated Product Manager, Scrum Master, Engineering Manager, QA engineers, frontend and backend engineers, and regular collaboration with UX designers. This setup gives engineers direct access to product context and a real opportunity to influence both technical and user-facing decisions.



What we offer:
  • Employment contract (17 708 - 19 792 PLN gross/monthly) OR B2B (147 - 164 PLN net/hourly)
  • Working with the newest technologies such as Cloud Computing (GCP)
  • Challenges at work that are difficult to find anywhere else!
  • Solving important problems in a scale
  • Joining a company that is growing and scaling
  • Flexible working hours & remote work option

  • Key responsibilities:
  • Design and build high-quality, maintainable user interfaces using JavaScript/TypeScript and React.
  • Develop and maintain Python-based backend APIs that support frontend workflows and product capabilities.
  • Translate business rules, pricing logic, and data dependencies into intuitive user experiences and reliable API integrations.
  • Own features end-to-end, from requirements and technical design through implementation, testing, rollout, and operational quality.
  • Write and maintain automated tests as part of the development process, including frontend and API-level tests where appropriate.
  • Collaborate closely with Product, UX, QA, and Engineering to deliver reliable product experiences for enterprise users.
  • Improve the usability, reliability, and maintainability of existing systems.
  • Contribute to technical direction, code quality, and engineering practices within the team.

  • Required Qualifications:
  • 4+ years of professional software engineering experience.
  • Experience building web applications with JavaScript or TypeScript.
  • Hands-on experience with React and modern frontend architecture.
  • Solid understanding of component-based development, state management, API integration, and frontend performance.
  • Experience designing and developing REST APIs or contributing to backend services, preferably in Python.
  • Practical understanding of databases and backend data flows.
  • Commitment to software quality, including writing automated tests where appropriate.
  • Strong ownership mindset and ability to collaborate effectively with Product, UX, QA, and Engineering.
  • Communicative Polish and English languages.

  • Desired Characteristics:
  • Experience with advertising technology, marketing technology, digital media, marketplace platforms, financial workflows, or revenue-related systems.
  • Experience with GraphQL.
  • Experience with cloud-based systems such as Google Cloud Platform, AWS, or Azure.

  • Technologies you will work with:
  • Frontend: TypeScript, React, single-page applications, React Testing Library.
  • API/backend: Python, REST APIs.
  • Testing: Playwright, pytest.
  • Data and infrastructure: PostgreSQL, Google Cloud Platform (GCP), Docker, Kubernetes, Terraform.
  • Delivery: CI/CD, Cloud Build, Spinnaker.
  • Tooling: modern AI-assisted development tools.
  • Collaboration: GitHub, code reviews, engineering communities of practice.

  • Our benefits (on employment contract):
  • Annual performance bonus
  • Tax-deductible system due to copyright protection: 75%
  • Private health care for you and your family (covered by OpenX)
  • Private life and travel insurance
  • MultiKafeteria program 
  • Training: access to the LinkedIn learning platform and Tech workshops 
  • Holiday Allowance
  • Pension scheme (PPK from PZU)
  • Additional paid day off 
  • Free parking lot 
  • Access to peer to peer recognition platform
  • Monthly work-from-home allowance and one-time payment when you join us to help you set up your home office
  • We celebrate team members' important personal milestones (vouchers, gifts)