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Full-time jobsthe United States

Senior Staff Machine Learning Systems Engineer, Indexing & Retrieval Search

reddit · Remote - United States · Full-time

About this role

Reddit is a community of communities. It’s built on shared interests, passion, and trust, and is home to the most open and authentic conversations on the internet. Every day, Reddit users submit, vote, and comment on the topics they care most about. With 100,000+ active communities and approximately 126 million daily active unique visitors, Reddit is one of the internet’s largest sources of information. For more information, visit www.redditinc.com .

Team The ML Indexing & Retrieval Platform team at Reddit is responsible for building and scaling the core infrastructure that powers machine learning driven recommendations. We design and maintain systems for ML data ingestion, low-latency retrieval services, and end-to-end lifecycle management of data. With a focus on performance, reliability, and scalability, we enable real-time access to high-quality data that supports a wide range of applications, including Content Understanding, Semantic, Lexical retrieval & GenAI applications. 

How You'll Have Impact

You’ll lead the development of next-generation ML Indexing & Retrieval systems, owning the full lifecycle from ideation to production and going beyond incremental improvements to reimagine core platform capabilities. As part of a high-impact, cross-functional team, you’ll solve complex technical challenges to build scalable, reliable platforms that empower developers to efficiently ship critical ML features.

Languages: Go, Java, Python, or any object oriented programming language

Frameworks: Flink, Airflow, Spark for large scale batch & stream processing 

Databases: Familiarity with Vector, Lexical & Key-Value Databases 

Tools: Kubernetes, Docker, AWS, GCP

What You’ll Do

• Lead the technical strategy, architecture, and implementation of Reddit’s next-generation ML Indexing & Retrieval engine, integrating capabilities across lexical and vector indexing, low-latency retrieval, and emerging GenAI applications.

• Partner closely with product engineers across Content Understanding, Search, Feeds, Ads, Growth, and Safety to deliver high-quality experiences.

• Define best practices for observability, reliability, and operational excellence in large-scale distributed systems.

• Mentor and guide engineers in designing scalable infrastructure and adopting robust DevOps and SRE principles.

• Collaborate with infrastructure, and ML teams to ensure the platform evolves to meet the needs of Reddit’s growing user base and diverse content ecosystem.

Who You Might Be:

• 10+ years of experience in software engineering, specializing in Indexing and Retrieval systems.

• 3+ years in technical leadership, architecting and scaling distributed systems in production environments.

• Deep expertise in large-scale data platforms, including batch indexing and stream processing.

• Proven experience designing and operating large-scale, low-latency retrieval services.

• Expertise in lexical and vector se

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