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Senior JavaScript Engineer(AdTech)

  • Remote
    • Poland, Mazowieckie, Poland
  • T_CPA

Job description

Are you passionate about modern frontend development and curious about the inner workings of digital advertising? We’re looking for a Senior JavaScript Engineer to join our dynamic team and take a key role in building and optimizing our in-house Header Bidding and ML-powered yield-management stack for publishers.

This is more than a traditional engineering role — we’re launching a new strategic direction in digital marketing, and we’re looking for someone who’s not only technically strong but also naturally investigative. You’ll lead data-driven experiments, explore new concepts, and help shape the next generation of AdTech solutions based on your findings.

What you will do:

  • Set up a lightweight and efficient Prebid.js integration (under 30 KB) with support for 5 major ad bidders like Magnite and OpenX.

  • Build a high-performing sticky ad widget that refreshes smartly — only when the ad stays visible for at least 30 seconds and has 60%+ viewability.

  • Implement out-stream video ads (ads that play outside of a video player) using VideoJS and Google’s IMA SDK for seamless ad playback.

  • Configure and manage Google Ad Manager, including setting up line items, sending MCM (Multiple Customer Management) invites, and using automation scripts to streamline tasks.

  • Integrate a Consent Management Platform (CMP) to comply with privacy regulations, and develop a tool to validate ads.txt files, ensuring authorized ad inventory.

  • Create data views in BigQuery using SQL to analyze key monetization metrics like eCPM and Invalid Traffic (IVT), applying logic such as percentiles for deeper insights.

Job requirements

Who you are:

  • Senior-level experience with JavaScript/TypeScript (ES6+, Webpack or Vite, DOM performance)

  • Solid understanding of HTTP, browser DevTools, and CORS

  • Proven experience building production-ready widgets or SPAs

  • Strong analytical and problem-solving skills

  • English B2+: able to read technical documentation and write clear tickets

  • Quick learner, comfortable navigating complex systems

We're building smart solutions for a fast-moving industry — and we want curious, driven engineers like you on board. Apply today!

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