Machine Learning Engineer, Answers Relevance

Details

Reddit's Answers Relevance team uses AI to connect people with relevant information from Reddit communities. The team is hiring Senior and Staff Machine Learning Engineers to improve the relevance, helpfulness, and intelligence of Reddit Answers.

Responsibilities

• Lead machine learning projects from idea through production in partnership with Product, Data Science, and Engineering teams across recommendations, search, messaging, and AI systems.
• Build and improve large-scale machine learning systems, including retrieval and ranking, embeddings, and LLM-powered features.
• Set technical direction and deliver measurable user and business impact.
• Work with partner teams to shape product and technical roadmaps.
• Evaluate new AI and machine learning approaches and support responsible LLM development.
• Mentor engineers and contribute to long-term machine learning planning.
• Define product success metrics, feedback loops, and evaluation approaches, including human review.

Areas of Experience

Experience in one or more of the following areas may be relevant:

• Recommendations, search, content understanding, or large-scale data and machine learning infrastructure.
• State-of-the-art large-scale recommender systems.
• Foundational retriever models.
• Retrieval-augmented generation (RAG) systems, retrieval methods, LLM evaluation, or production LLM features.
• Agentic AI, including tool calls, MCPs, multi-agent systems, and orchestration.
• Self-hosted open-weight models such as Qwen or Llama; prompt engineering, fine-tuning, post-training, or prompt optimization.
• Grounding, instruction following, hallucination reduction, and retrieval and generation quality evaluation.
• Scaling LLM systems, including latency, caching, cost optimization, and safety measures for prompt injection and unsafe inputs.

Requirements

• 4–12 years of experience building, deploying, and operating machine learning systems in production.
• Broad knowledge of machine learning fundamentals and experience applying them in production.
• Experience developing and productionizing models with TensorFlow, PyTorch, or Hugging Face Transformers.
• Experience writing production-quality code, including testing, evaluation, and monitoring.
• Python experience required; Golang experience is a plus.
• Experience with machine learning systems such as data pipelines, feature engineering, model training and serving, and production monitoring.
• Strong communication and collaboration skills, with a record of delivering measurable product impact.

Benefits

• Comprehensive healthcare benefits and income replacement programs.
• 401(k) with employer match.
• Global benefits programs covering workspace, professional development, caregiving support, and other needs.
• Family planning support.
• Gender-affirming care.
• Mental health and coaching benefits.
• Flexible vacation and paid volunteer time off.
• Generous paid parental leave.

Compensation

The base salary range for this position is $216,700–$322,000 USD. The position is also eligible for equity in the form of restricted stock units and may be eligible for a commission depending on the position offered.