Staff Machine Learning Engineer, Ranking and Personalization

The Developer Platform team is building the future of Reddit: a future where third-party developers, moderators and everyday redditors can invent and ship brand-new apps, games and tools that create entirely new ways for communities to play, connect and get things done at reddit. We power everything from interactive custom posts and daily games to mod tooling and data products, giving builds the primitives they need to create entirely new kinds of experiences on Reddit.

Within Developer Platform, our Growth team focuses on helping redditors discover the right apps and games at the right time through ranking, notifications, and cross‑surface entry points, directly moving the needle on engagement and DAU for Dev Platform experiences. You’ll work end‑to‑end with a highly collaborative, cross‑functional group of engineers, PMs, designers, and data scientists who value impact, personal growth, openness, and kindness, and who ship quickly while holding a high bar for reliability and performance across Reddit’s web, mobile, and backend stack.

How You'll Have Impact

We are looking for a Staff Machine Learning Engineer to build the ranking and personalization systems that connect redditors with their next favorite game or app on Reddit. You will work closely with Product, Backend, Data Science, and Core Ranking/ML Platform teams to design and ship best-in-class ranking, retrieval, and experimentation systems that power discovery and re-engagement for Dev Platform experiences across feeds, surfaces, and notifications.

You will own problems end-to-end—from framing objectives and defining signals, to training and deploying models, to designing experiments and reading results—not just tuning existing knobs on mature systems. You’ll help define the ranking strategy for Developer Platform, stand up new ML models and feedback loops where none exist today, and turn noisy behavioral data into clear wins for users, creators, and developers.

This is a high-impact, 0→1 role where your work will directly shape how interactive apps and games show up on one of the largest sites in the world. You’ll set technical direction for Dev Platform ranking, raise the bar on relevance and system reliability, and mentor other engineers as we scale a team of builders who value impact, personal growth, openness, and kindness.

Languages: Go, Python, C++ or any object oriented programming language

Libraries: Baseplate, GraphQL

Databases: Redis, Postgres, Memcached

Tools: Kubernetes, AWS

Tools: Kubernetes, Docker, AWS, GCP

What You’ll Do

• Design and ship next-generation ranking and personalization models that power discovery of Dev Platform apps and games across Reddit surfaces.
• Partner with ML, DS, and product to define signals, APIs, and feedback loops for building, deploying, and iterating on ranking models.
• Explore and productionize new retrieval, ranking, and experimentation approaches that unlock new Dev Platform experiences.
• Champion model quality, reproducibility, and experimentation best practices — including offline evaluation, A/B testing, and monitoring for model health and degradation
• Mentor engineers and lead technical discussions, shaping the long-term ranking and personalization modeling strategy for Dev Platform.

Who You Might Be

• 8+ years of experience building and deploying ML models in production, particularly in ranking or personalization modeling, large-scale representation learning, or recommender systems.
• Proven track record working on cross-functional product teams (PM, Design, DS, Eng) where you owned end-user outcomes, not just models or infra, and shipped features that moved core product metrics.
• Strong domain knowledge in modern ranking and personalization techniques: user/item embeddings, multi-task learning, sequential modeling, or similar approaches applied at scale.
• Experience designing and implementing performant, stable, and efficient ML or ranking systems (recommendation, ads, search, feed, or similar high-throughput decision systems).
• Strong organizational skills with the ability to prioritize, sequence, and de-risk work, keeping complex projects on schedule with a high attention to detail.
• BS in Computer Science or a related technical field, or equivalent practical experience.
• Comfortable with software engineering best practices: testing, code reviews, technical design docs, and clear documentation for other teams that depend on your systems.
• Entrepreneurial mindset: you are self-directed, comfortable in ambiguity, and biased toward action in fast-paced environments. You like 0→1 building, iteration, and learning from experiments and failures.
• Excellent communication skills: you collaborate effectively in a remote, cross-functional team, and can explain complex ML and ranking concepts to both technical and non-technical stakeholders.

Benefits:

• Comprehensive Healthcare Benefits and Income Replacement Programs
• 401k with Employer Match
• Global Benefit programs that fit your lifestyle, from workspace to professional development to caregiving support
• Family Planning Support
• Gender-Affirming Care
• Mental Health & Coaching Benefits
• Flexible Vacation & Paid Volunteer Time Off
• Generous Paid Parental Leave

#LI-remote

Pay Transparency:

This job posting may span more than one career level.

In addition to base salary, this job is eligible to receive equity in the form of restricted stock units, and depending on the position offered, it may also be eligible to receive a commission. Additionally, Reddit offers a wide range of benefits to U.S.-based employees, including medical, dental, and vision insurance, 401(k) program with employer match, generous time off for vacation, and parental leave. To learn more, please visit https://www.redditinc.com/careers/.

To provide greater transparency to candidates, we share base salary ranges for all US-based job postings regardless of state. We set standard base pay ranges for all roles based on function, level, and country location, benchmarked against similar stage growth companies. Final offer amounts are determined by multiple factors including, skills, depth of work experience and relevant licenses/credentials, and may vary from the amounts listed below.

In select roles and locations, the interviews will be recorded, transcribed and summarized by artificial intelligence (AI). You will have the opportunity to opt out of recording, transcription and summarization prior to any scheduled interviews.

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Reddit is proud to be an equal opportunity employer, and is committed to building a workforce representative of the diverse communities we serve. Reddit is committed to providing reasonable accommodations for qualified individuals with disabilities and disabled veterans in our job application procedures. If, due to a disability, you need an accommodation during the interview process, please let your recruiter know.