Senior JavaScript Engineer

  • Full time
  • Prague
  • Posted 3 months ago


Node.js (nice to have)
Redux (regular)
REST (regular)
Apollo (regular)
GraphQL (regular)
CI/CD (advanced)
GCP (advanced)
React (advanced)
JavaScript (master)
Who we are:
OpenX is a top player in the AdTech industry in the World specializing in programmatic advertising, powering monetization and advertising revenue for publishers (i.e. websites, mobile apps, CTV and OTT apps, etc.), and providing highly targeted audiences for advertisers, brands, and agencies. We have seven offices located around the globe (in the US, the UK, Poland, and Japan). Our Ad Exchange platform handles billions of ad requests daily connecting thousands of publishers with demand partners. It’s fully containerized running in the cloud in multiple regions across the world. That’s the place where each millisecond matters. 
We are operating at a scale:
100% Cloud-based (GCP) platform
Over 250 billion Ad requests every day
Over 120 000 CPU daily
Over 140 TB RAM daily
Over 50 PB of data per week
Over 1200 production deployments a month
Who we are looking for
At OpenX Poland, we’re looking for talented, communicative, and curious engineers to join our amazing team in Cracow, Poland. Currently, we’re looking for a Senior Software Engineer (JavaScript).
You will be part of the core exchange development team. Our exchange handles billions of ad requests daily connecting thousands of publishers with demand partners. It’s fully containerized running in the cloud in multiple regions across the world. Ads from our systems can be seen in your favored mobile game, web page, maybe TV in the future. That’s the place where each millisecond matters.
You will be working on Marketplace Quality (Traffic Quality and Ad Quality). Recognize non-human traffic and block it to reduce the cost of our infrastructure and to not overload our demand-side partners, detect malware in ads, check if they meet standards and keep websites and visitors safe, provide a response in a few milliseconds if the quality of traffic and ads is good for 80 billions of requests per day.

What we offer
  • Working with the newest technologies such as Cloud Computing (GCP)
  • Experienced Team (50% of the company are senior developers!)
  • 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 high-performance, distributed, low-latency systems
  • Architect, create, and deliver new features and functionality
  • Work with Product to drive the requirements, and own the project end-to-end
  • Work with Product and UX teams to bring consumer-grade user experience and design to the
  • enterprise
  • Work with Engineering and Product teams distributed across multiple locations
  • Analyze and improve efficiency, scalability, and stability of servers and processes
  • Think long-term and be unsatisfied with band-aids
  • Identify unnecessary complexity and remove it

Required Qualifications
  • 5+ years experience with building SaaS applications using JavaScript/Typescript (including Node.js)
  • Experience with databases system design, RDBMs, or NoSQL
  • Excellent written and spoken English skills
  • Experience with Amazon Web Services or Google Cloud Platform
  • Experience working in digital media, marketing technology, or advertising technology is a big plus
  • Communicative Polish and English

Desired Characteristics
  • Good written & oral communication skills, excellence
  • Good sense of humour
  • Team player
  • Self-starter with the ability to independently identify and act on areas of improvement
  • Ability to rapidly learn and understand new systems

Our benefits
  • Annual performance bonus
  • Private health care for you and your family (covered by OpenX)
  • Private life and travel insurance (Covid insurance included)
  • MultiKafeteria program 
  • Training: access to the LinkedIn Learning platform, Tech workshops, English lessons
  • Holiday Allowance
  • Pension scheme (PPK from PZU)
  • Additional paid day off 
  • Free parking lot 
  • Sports activities: online yoga/stretching classes 🙂
  • Access to peer to peer recognition platform
  • Possible trips to California once in a while 
  • Company events (online during the pandemic time)
  • 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)

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