Middle node.js developer (adtech)

Our client operates an established real-time advertising exchange platform built on OpenRTB, in the ad exchange / adtech space. They're looking for a Middle Node.js Developer to join the backend engineering team supporting and evolving the platform. This is a backend-only role. What You'll Work On Backend development: Build, maintain, and evolve backend services for an OpenRTB-based ad exchange platform. Automated testing: Writing and maintaining automated tests is a core, ongoing part of the role. Team collaboration: Work closely with the Tech Lead and a small, focused team — a DevOps engineer, a UI specialist, and another backend developer. Who We're Looking For A solid, mid-level developer who is focused, responsible, communicative, and open to learning. Technical gaps can be closed on the job; attitude and work ethic matter just as much as the checklist below. Requirements Node.js — 3+ years of experience, mid-level proficiency SQL databases: MySQL or PostgreSQL Comfortable with SSH and Linux Experience writing automated tests Nice to Have Experience in adtech, ideally with OpenRTB NoSQL experience: MongoDB, Redis AI fluency in software development Before You Apply: Please answer the screening questions in your application. We're only able to follow up with candidates who respond to them, and — for developers without direct adtech/OpenRTB experience — we'll reach out to those whose overall profile looks like a strong match for the role. What We Offer Compensation: $3,000–$3,500/month gross for candidates with adtech/OpenRTB experience; up to $2,500/month gross for strong developers without an adtech background Employment: FOP (sole proprietorship) contract, Ukraine Schedule: Ukrainian time zone Vacation: Flexible / unlimited Before You Apply: Please answer the screening questions in your application. We're only able to follow up with candidates who respond to them, and — for developers without direct adtech/OpenRTB experience — we'll reach out only to those whose overall profile looks like a strong match for the role. The questions are below: Have you worked on adtech systems? If so, describe your most substantial hands-on experience with OpenRTB or a similar RTB/programmatic protocol — what platform, what part of the flow did you personally build or maintain (bidder, exchange-side integration, ad server, bid stream processing), and at what scale (QPS, daily bid volume)? If you haven't worked in adtech, say so directly — it's not a disqualifier for this role. Describe the most complex backend service or system you've built in Node.js in production — what problem it solved, your specific role in building it, and the biggest technical challenge you had to solve. What's your approach to automated testing on a backend service — what do you actually cover (unit, integration, contract tests), which tools/frameworks, and can you give an example of a bug your test suite recently caught before it hit production? Interview Process Screening interview with DNA325 Interview with the Tech Lead Live coding session