Principal Software Engineer

Who We Are

Kargo creates powerful moments of connection between brands and consumers to build businesses. Every day, our 600+ employees work to radically raise the bar on what agentic AI, CTV, eCommerce, social, and mobile can do to deliver unique ad experiences across the world's most premium platforms. Taking a creative science approach to all we do, we continuously innovate solutions that outperform industry benchmarks and client expectations. Now 20+ years strong, Kargo has offices in NYC, Chicago, LA, Dallas, Sydney, Auckland, London and Waterford, Ireland.


Who We Hire

Techies who want to build the future. Creatives who want to design it better. Communicators to win business. Collaborators to build it. Data pros who turn numbers into insights. Product builders who turn ideas into innovations. Anyone eager to be on a team that doesn't stop to ask what's next, because they're already building it.


Mission

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.

This is a hybrid role with a requirement to be onsite 4 days per week.

Outcomes - What Success Looks Like in 6-12 Months

• Delivered a cross-team architectural initiative. Designed and shipped at least one major system or architectural change spanning multiple teams, carried from strategy through production rollout and adoption.
• Set the technical direction for ad delivery. Anticipated industry standards, programmatic shifts, and scaling demands, and repositioned the platform ahead of the curve with measurable business impact.
• Became the recognized authority on ad serving. Established as the org's go-to expert on SSP architecture and real-time bidding decisions, and a trusted advisor to engineering leadership on high-stakes calls.
• Raised the technical bar across the department. Mentored Staff and Senior Engineers with measurable impact on their growth and promotion readiness, creating capability that outlasts individual projects.
• Drove org-wide adoption of new practices. Moved new technologies, patterns, or standards from POC to production across multiple teams, improving quality, scalability, or velocity beyond a single team.

Skills - Core Technical Capabilities

Required

• 12+ years building and maintaining production systems, with deep ad tech or programmatic experience
• Expert across multiple languages and frameworks , including those active on the team (Go, 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: 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

Preferred

• 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

Competencies - Behaviors We Like to See

Strategic technical leadership

• Builds multi-year technology strategy for business-critical areas that cross multiple systems and teams
• Makes high-stakes, long-horizon technical decisions and is trusted to balance business needs against technical excellence

Influence without authority

• Drives adoption of new technologies and patterns through demonstration and credibility, not mandate
• Resolves the most complex challenges that span multiple teams or product areas, and establishes standards others choose to follow

Sustained high-impact delivery

• Carries complex, multi-team initiatives from concept to production and across the finish line
• Ships code that's well-reasoned and tested, with a clear recovery plan when things go wrong

Developer of technical talent

• Mentors Staff and Senior Engineers with measurable impact on their growth and promotion readiness
• Raises the bar through code reviews, architectural guidance, and knowledge sharing that becomes a force multiplier

In accordance with applicable federal, state, and local pay transparency laws, the anticipated base salary range for this position is listed below. Actual compensation may vary based on factors such as geographic location, work experience, education, and skills.

U.S Salary Range


$230,000-$250,000 USD

Our Laurels

• AdAge Best Places to Work
• ThinkLA Partner of the Year
• Built In Best Places to Work
• Cynopsis 2025 Top Women in Media - Jeannine Shao Collins
• Martech Breakthrough Awards - Best Overall Adtech Company
• Digiday Media Awards Best Event
• Cynopsis Media Impact Awards-Best CTV Platform
• Martech Breakthrough Awards-CTV Innovation
• Adweek Media Plan of the Year Awards - Best Use of Insights

Follow Our Lead

• Big Picture: kargo.com
• The Latest: Instagram (@kargomobile) and LinkedIn (Kargo)

Kargo is an Equal Opportunity Employer. We are committed to building an inclusive and diverse workplace where all employees and applicants are treated with respect and dignity. We do not discriminate on the basis of race, color, ethnic origin, religion or belief, sex, sexual orientation, gender identity or expression, age, disability, marital or family status, national origin, veteran status, or any other characteristic protected by applicable local, state, or federal law. All qualified applicants will receive consideration for employment.

Pursuant to applicable fair chance laws, including the San Francisco Fair Chance Ordinance and the Los Angeles Fair Chance Initiative for Hiring, Kargo will consider qualified applicants with arrest and conviction records for employment.