What Ads Engineers Actually Build
Ads engineering spans from ad serving to measurement.
Ad Serving Systems
Delivering ads to users:
- Ad selection — Choosing which ad to show
- Auction systems — Running real-time bidding
- Pacing — Spending budgets evenly over time
- Frequency capping — Limiting ad exposure
- Creative serving — Delivering ad content
Bidding and Optimization
Maximizing advertiser value:
- Bid optimization — Predicting click/conversion probability
- Budget optimization — Allocating spend effectively
- Targeting — Reaching the right users
- Campaign management — Advertiser controls
- Auto-bidding — ML-driven bidding strategies
Measurement Systems
Proving ad effectiveness:
- Attribution — Connecting ads to outcomes
- Conversion tracking — Measuring user actions
- Reporting — Advertiser dashboards
- Experimentation — Measuring incrementality
- Privacy-preserving measurement — Post-cookie solutions
Ads Technology Stack
Core Systems
| System | Requirements |
|---|---|
| Ad server | <100ms latency, millions QPS |
| Bidding | Real-time ML inference |
| Targeting | Large-scale user data |
| Measurement | Cross-device attribution |
Infrastructure
- Serving: Custom high-performance systems
- ML: TensorFlow, PyTorch for prediction
- Data: Kafka, Spark for event processing
- Storage: Distributed systems for scale
Skills by Experience Level
Junior Ads Engineer (0-2 years)
Capabilities:
- Implement ad serving features
- Build measurement pipelines
- Support bidding systems
- Analyze campaign performance
- Write performant code
Learning areas:
- Auction mechanics
- ML for bidding
- System design at scale
- Privacy considerations
Mid-Level Ads Engineer (2-5 years)
Capabilities:
- Design ad system components
- Implement bidding algorithms
- Build targeting systems
- Optimize for latency
- Handle campaign logic
- Mentor juniors
Growing toward:
- Architecture decisions
- ML model ownership
- Technical leadership
Senior Ads Engineer (5+ years)
Capabilities:
- Architect ads platforms
- Lead bidding strategy
- Design privacy-preserving systems
- Handle billions of requests
- Drive ads product direction
- Mentor teams
Curiosity & fundamentals
Independence & ownership
Architecture & leadership
Strategy & org impact
Interview Focus Areas
Technical Fundamentals
- "Explain how a real-time bidding auction works"
- "How do you predict click-through rate?"
- "What's the difference between first-price and second-price auctions?"
- "How do you handle latency requirements in ad serving?"
System Design
- "Design an ad serving system for a major publisher"
- "How would you build a budget pacing system?"
- "Design an attribution system for cross-device measurement"
ML for Ads
- "How do you build a click prediction model?"
- "How do you handle class imbalance in conversion prediction?"
- "How do you evaluate a bidding model?"
Common Hiring Mistakes
Underestimating Scale Requirements
Ads systems process billions of requests with strict latency. Engineers without high-scale experience need significant ramp-up. Look for experience with systems at similar scale.
Ignoring Domain Knowledge
Auction mechanics, pacing, attribution—ads has specialized concepts. Generic engineers need to learn the domain. Prioritize ads or related experience.
Missing Privacy Awareness
Post-cookie advertising requires new approaches. Engineers who only know cookie-based targeting may struggle. Evaluate awareness of privacy-preserving techniques.
Overlooking Business Understanding
Ads is ultimately about ROI for advertisers. Engineers who don't understand the business context build technically correct but commercially useless systems.
Where to Find Ads Engineers
High-Signal Sources
Ads engineers primarily come from ad platforms (Google, Meta, Amazon), ad tech companies (The Trade Desk, Criteo, AppLovin), and large publishers with programmatic operations. The concentration of ads engineering talent in these companies is high. Look for candidates who've worked on bidding systems, ad serving, or measurement specifically.
Conference and Community
AdExchanger conferences attract ad tech professionals. Programmatic I/O events surface practitioners. The ad tech community on LinkedIn and industry-specific Slack groups (AdOps, Programmatic) can help with sourcing.
Company Backgrounds That Translate
- Ad platforms: Google, Meta, Amazon, Microsoft (Bing Ads)—direct experience
- Ad tech: The Trade Desk, Criteo, AppLovin, InMobi—DSP/SSP expertise
- Publishers: Large media companies with programmatic ad operations
- E-commerce: Retail media networks (Instacart Ads, DoorDash Ads) growing fast
- Gaming: In-game advertising and rewarded video networks
Emerging Opportunity Areas
Privacy-preserving advertising (cookieless targeting, Privacy Sandbox), retail media networks, and connected TV advertising are growth areas attracting talent.
Recruiter's Cheat Sheet
Resume Green Flags
- Ads platform experience (Google, Meta, etc.)
- Real-time bidding systems
- High-scale system experience
- ML for prediction/bidding
- Measurement/attribution experience
Resume Yellow Flags
- No ads or high-scale experience
- Only batch processing
- Cannot discuss latency requirements
- No business context understanding
Technical Terms to Know
| Term | What It Means |
|---|---|
| RTB | Real-Time Bidding |
| CTR | Click-Through Rate |
| CVR | Conversion Rate |
| DSP | Demand-Side Platform |
| SSP | Supply-Side Platform |
| Attribution | Connecting ads to outcomes |
| Pacing | Spreading budget over time |