Principal Software Engineer

Kargo•New York, NY

12d•$230,000 - $250,000•Hybrid

About The Position

The Principal Engineer for Surface Ad Delivery (SAD) owns the technical strategy and architecture for the ad serving infrastructure behind Kargo's programmatic platform at scale. The SAD team carries full-stack responsibility for real-time bidding, partner integrations, exclusive inventory expansion, proprietary ad formats, and delivery across web, mobile, and DOOH. When this role is firing on all cylinders, the platform is positioned ahead of industry and scaling shifts, the hardest architectural problems have a clear owner, and the team is building on patterns set years before the rest of the market catches up.

Requirements

12+ years building and maintaining production systems, with deep ad tech or programmatic experience
Expert across multiple languages and frameworks, including Go and Node.js
Deep expertise in the OpenRTB protocol and real-time bidding — proven track record designing SSP/DSP integrations, bid adapters, or programmatic platforms at scale
Strong full-stack web architecture: HTTP/CORS, RESTful APIs, client-side JavaScript, browser rendering, and backend services, with the judgment to architect across them
Working command of video and mobile ad standards (VAST/VPAID, MRAID), including debugging complex rendering and tracking issues
Proven ability to debug the team's toughest problems in production, and to influence technical direction across the org without direct authority

Nice To Haves

Header bidding, SSP platforms, or DOOH advertising, including ad format rendering across web, mobile, and DOOH surfaces
Prior Staff Engineer, Tech Lead, or equivalent technical leadership role

Responsibilities

Owns the technical strategy and architecture for the ad serving infrastructure.
Carries full-stack responsibility for real-time bidding, partner integrations, exclusive inventory expansion, proprietary ad formats, and delivery across web, mobile, and DOOH.
Delivered a cross-team architectural initiative, spanning from strategy through production rollout and adoption.
Set the technical direction for ad delivery, anticipating industry standards, programmatic shifts, and scaling demands.
Became the recognized authority on ad serving, establishing expertise in SSP architecture and real-time bidding decisions.
Raised the technical bar across the department by mentoring Staff and Senior Engineers.
Drove org-wide adoption of new practices, moving new technologies, patterns, or standards from POC to production.