EPAM is a leading global provider of digital platform engineering and development services. We are committed to having a positive impact on our customers, our employees, and our communities. We embrace a dynamic and inclusive culture. Here you will collaborate with multi-national teams, contribute to a myriad of innovative projects that deliver the most creative and cutting-edge solutions, and have an opportunity to continuously learn and grow. No matter where you are located, you will join a dedicated, creative, and diverse community that will help you discover your fullest potential. We are seeking a Lead Software Engineer (AdTech) to architect and build high-performance ad serving systems on the hot path. This is an individual contributor role where you will set technical direction across ad serving, SSAI, RTB and identity, mentor senior engineers and represent our technical position with major industry partners. You will own auction-level economics, quantifying the revenue impact of every millisecond of latency and every dollar of infrastructure spend. Responsibilities Architect and write code on the hot path as a hands-on individual contributor Set technical direction on ad serving, SSAI, RTB and identity through design docs that you write, defend and update as reality dictates Mentor engineers by setting the bar on code review, production discipline and how the team reasons about latency, cost and correctness Own auction-level economics and quantify the revenue-per-thousand-impression consequence of latency and AWS spend on the ad path Represent the company's technical position with partners including GAM, SSPs, DSPs, measurement vendors and IAB Tech Lab Set the hiring bar for future engineers and participate in the loop on every senior+ AdTech hire Drive production ownership of systems serving hundreds of millions of ad requests per day Make and defend judgment calls to reject features that compromise latency, correctness or unit economics Requirements 5+ years of professional software engineering experience, with at least 3 years inside an SSP, DSP, ad server, ad exchange or CTV/OTT platform Production ownership of a system that has served at least hundreds of millions of ad requests per day Deep proficiency in at least one systems language for the hot path: Go, Java, C++ or Rust, with working comfort in another Working-spec-level command of OpenRTB (2.x and 3.x), VAST (3 and 4), VPAID, VMAP and SIMID Direct experience with SSAI including pod construction, manifest manipulation, ad stitching and the failure modes of delivering ads inside HLS or DASH streams Header-bidding architecture experience including Prebid.js client-side, Prebid Server, wrapper design and price-floor strategy Engineer-level expertise with Google Ad Manager APIs, the line-item and key-value model and where the abstractions leak AWS at scale with specific fluency in EC2/EKS, ECS and Lambda, plus DynamoDB, Kinesis, MSK/Kafka and CloudFront Distributed systems literacy across queueing theory, backpressure, idempotency, hot-key mitigation and multi-region failover FinOps instinct with a clear understanding of stack cost per thousand ad requests Capability to use React where it touches ad-ops surfaces Advanced proficiency in English (C1+) Nice to have Background in FinOps Platforms Expertise in Golang and distributed systems We offer International projects with top brands Work with global teams of highly skilled, diverse peers Employee financial programs Paid time off and sick leave Upskilling, reskilling and certification courses Unlimited access to the LinkedIn Learning library and 22,000+ courses Global career opportunities Volunteer and community involvement opportunities EPAM Employee Groups Award-winning culture recognized by Glassdoor, Newsweek and LinkedIn #J-18808-Ljbffr