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Lead Software Engineer (C++) - Ad Tech & Distributed Systems - FreeWheel

Comcast · IL · $152,829–$229,243 a year · Full time

Posted Aug 7, 2026 · We last checked this listing on Oct 6, 2026

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Likely interview questions for this role

Written from this job description, not a generic list. Each one notes what the interviewer is really checking.

About your past

Tell me about a performance improvement you made that had a measurable impact.

What they are checking: Whether they can show real results from optimization work.

Tell me about a time you led a technical design that other engineers had to adopt.

What they are checking: Whether they can lead and influence as a lead engineer.

How do you mentor engineers who are newer to C++ or distributed systems?

What they are checking: Whether they help grow the team's skills, which a lead role requires.

What would you do

A new release raises memory usage in production. How do you investigate?

What they are checking: Whether they can track down memory leaks or growth in a live system.

How do you decide between using modern C++ features and keeping code simple for the team?

What they are checking: Whether they balance language power with code that the whole team can read and maintain.

About the work

How would you design a C++ service that handles millions of concurrent ad requests with very low latency?

What they are checking: Whether they understand threading, memory and I/O design for high-throughput systems.

What causes latency spikes in C++ services, and how do you find them?

What they are checking: Whether they can profile and fix tail latency, which hurts ad auctions.

How do you avoid lock contention in a highly concurrent C++ application?

What they are checking: Whether they know lock-free structures, sharding and other concurrency techniques.

How would you integrate with an external demand partner that responds slowly or unreliably?

What they are checking: Whether they protect the platform from partner failures with timeouts and fallbacks.

How do you test decisioning logic that depends on real-time data?

What they are checking: Whether they can build reliable tests for complex, data-dependent behavior.

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The full job description

As published by Comcast.

FreeWheel, a Comcast company, provides comprehensive ad platforms for publishers, advertisers, and media buyers. Powered by premium video content, robust data, and advanced technology, we’re making it easier for buyers and sellers to transact across all screens, data types, and sales channels. As a global company, we have offices in nine countries and can insert advertisements around the world. Job Summary We are seeking a Senior Software Engineer (C++) to join a team responsible for building and enhancing a large-scale, real-time advertising platform that operates at massive scale. This role focuses on developing high-performance backend services that process millions of concurrent requests, optimize ad delivery decisions, and maintain ultra-low latency response times across a distributed cloud infrastructure. The ideal candidate has deep expertise in C++ development, distributed systems, concurrency, and high-throughput application design. You'll work on mission-critical services that sit at the core of the advertising ecosystem, handling complex decisioning logic and real-time integrations with external demand partners and marketplaces. Job Description Core Responsibilities • Design, develop, and optimize high-performance C++ applications that power a large-scale ad serving platform. • Build and maintain backend systems capable of processing millions of concurrent requests with low latency and high availability. • Develop new platform capabilities while ensuring system stability, scalability, and performance under heavy workloads. • Enhance systems that process ad requests, communicate with external bidding partners, evaluate responses, and return optimized decisions in real time. • Design and implement resilient distributed services across multi-region cloud environments. • Optimize application performance for high Query Per Second (QPS) workloads and high-concurrency traffic patterns. • Collaborate with engineering teams to architect failover, disaster recovery, and high-availability solutions. • Create efficient database queries and data access layers utilizing MySQL and Aerospike. • Troubleshoot performance bottlenecks across application, database, and infrastructure layers. • Participate in architecture discussions, code reviews, and technical design initiatives. • Monitor and continuously improve system reliability, scalability, and operational efficiency. Required Qualifications • Bachelor's degree in Computer Science, Engineering, or equivalent practical experience. • 5+ years of professional software development experience using C++ . • Experience building and supporting high-volume, high-concurrency distributed systems . • Strong understanding of multithreading, concurrency, memory management, and performance optimization. • Experience designing and operating low-latency, real-time applications . • Knowledge of cloud platforms including AWS, Azure, or GCP . • Experience working with relational databases, particularly MySQL . • Familiarity with distributed data stores such as Aerospike, Kafka, Snowflake, etc . • Strong understanding of scalable microservices and service-oriented architectures. • Experience with monitoring, troubleshooting, and performance tuning large-scale production systems. Comcast is an EOE/Veterans/Disabled/LGBT employer. Skills AWS OpsWorks, C++ Programming Language, Python (Programming Language), Systems Design Compensation Illinois Pay Range: $152,828.79 - $229,243.19 Comcast intends to offer the selected candidate base pay within this range, dependent on job-related, non-discriminatory factors such as experience. The application window is 30 days from the date job is posted, unless the number of applicants requires it to close sooner or later. Base pay is one part of the Total Rewards that Comcast provides to compensate and recognize employees for their work. Most sales positions are eligible for a Commission under the terms of an applicable plan, while most non-sales positions are eligible for a Bonus. Additionally, Comcast provides best-in-class Benefits to eligible employees. We believe that benefits should connect you to the support you need when it matters most, and should help you care for those who matter most. That’s why we provide an array of options, expert guidance and always-on tools, that are personalized to meet the needs of your reality – to help support you physically, financially and emotionally through the big milestones and in your everyday life. Please visit the compensation and benefits summary on our careers site for more details. Education Bachelor's Degree While possessing the stated degree is preferred, Comcast also may consider applicants who hold some combination of coursework and experience, or who have extensive related professional experience. Certifications (if applicable) Relevant Work Experience 10 Years + Comcast is an equal opportunity workplace. We will consider all qualified applicants for employment without regard to race, color, religion, age, sex, sexual orientation, gender identity, national origin, disability, veteran status, genetic information, or any other basis protected by applicable law.

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