# Machine Learning Engineer, Ads Optimization & Ads Marketplace Quality
**Company:** [Reddit](https://hotfix.jobs/companies/reddit)
**Location:** Remote
**Salary:** $186K-$303K
**Experience:** 3+ years
**Skills:** Python, Java, Go, Spark, Kafka, Airflow, BigQuery, Redis, Machine Learning, Optimization Algorithms, Bidding Systems, Auction Design, Pacing, Budget Optimization
**Posted:** 2026-06-26
> Build and evolve auction, bidding, and budgeting ML systems that power Reddit Ads. Design optimization algorithms balancing advertiser performance, user experience, and marketplace efficiency.
## Job Description
## Responsibilities

### Auction, Bidding, and Pacing Systems
- Design and implement models and policies that compute bids for different optimization objectives (CPC, CPA, ROAS-based strategies).
- Pace budgets smoothly over time across accounts, campaigns, and ad groups while preventing overspend or underspend.
- Allocate spend and auction participation intelligently across segments, surfaces, and time zones.
- Translate product and marketplace goals into concrete optimization problems and constraints (ROI, revenue, delivery smoothness, fairness, user experience).

### Marketplace Quality and Optimization
- Improve ad matching and ranking by incorporating new quality and relevance signals into bidding and auction decisions.
- Inform policies around ad load and eligibility that protect user experience while increasing high-quality ad opportunities.
- Integrate new bid strategies and pacing mechanisms into the broader ads ecosystem and measurement stack.

### General
- Own systems end-to-end: from problem formulation and algorithm design to experimentation, production deployment, and ongoing iteration.
- Work across Ads Optimization (bid strategies, budget optimization, pacing) or Ads Marketplace Quality (ad matching, ad load, quality controls).

## Requirements
- 3–5+ years of experience building, deploying, and operating machine learning systems in production (5+ years for IC4).
- Strong programming skills in Python, Java, Go, or similar languages, with solid software engineering fundamentals.
- Experience designing scalable data processing systems (Spark, Kafka, Airflow, BigQuery, Redis).
- Demonstrated ability to translate ambiguous product or business problems into solutions and improve measurable metrics.
- Evidence of stronger math and optimization skills: degree or equivalent background in a quantitative field (math, physics, quantitative finance, economics, operations research).
- Work experience in optimization-heavy domains (bidding/auctions, pacing, pricing, logistics optimization, quantitative finance).
- Comfort reasoning about and implementing custom optimization logic (gradient-based methods, constraint handling).

## Preferred Qualifications
- Experience with advertising/auction systems, online marketplaces, or search/ranking systems at scale.
- Experience in bidding, pacing, budget optimization, auction design, mechanism design, marketplace quality, or campaign performance optimization (CTR/CVR, CPA, ROAS).
- Familiarity with large-scale, real-time decision systems and low-latency production environments.
- Background in feature engineering, model optimization, and production monitoring for ML systems.
- Experience collaborating with cross-functional partners (Product, DS, Eng) in Ads or marketplace contexts.
- Advanced degree (MS or PhD) in Computer Science, Machine Learning, Operations Research, Applied Math, or a related quantitative field.

## Benefits
- Comprehensive Healthcare Benefits and Income Replacement Programs
- 401k with Employer Match
- Global Benefit programs (workspace, professional development, caregiving support)
- Family Planning Support
- Gender-Affirming Care
- Mental Health & Coaching Benefits
- Flexible Vacation & Paid Volunteer Time Off
- Generous Paid Parental Leave
**Apply:** https://hotfix.jobs/jobs/machine-learning-engineer-ads-optimization-ads-marketplace-quality-at-reddit-1b6a57d4-f904-4b39-9f4f-b4537e33b7e7
**Canonical:** https://hotfix.jobs/jobs/machine-learning-engineer-ads-optimization-ads-marketplace-quality-at-reddit-1b6a57d4-f904-4b39-9f4f-b4537e33b7e7