# AI Engineer, Applied ML

**Company:** [Perplexity](https://hotfix.jobs/companies/perplexity)
**Location:** San Francisco, CA, Palo Alto, CA, New York, NY
**Role:** ML Engineering
**Salary:** $220k – $405k/yr
**Experience:** 5+ years
**Skills:** PyTorch, TensorFlow, JAX, Python, LLMs, NLP, Information Retrieval, Recommendation Systems, RAG
**Posted:** 2025-09-19

> Designs, builds, and iterates on AI/ML models for personalization, query understanding, and content discovery. Requires 5+ years in ML, deep learning expertise (PyTorch/TensorFlow/JAX), Python, and full ML lifecycle ownership.

## Job Description

## Key Responsibilities
- Apply state-of-the-art ML and LLM techniques to solve problems spanning:
  - Personalization (LLM memory, context summarization, retrieval and ranking)
  - Query Understanding (intent modeling, rewriting, agentic decomposition)
  - Content Discovery (feed ranking and surfacing)
- Rigorously evaluate LLM/ML models with both offline and online techniques, designing experiments and metrics that provide deep insight into quality and impact
- Own the entire model lifecycle from research to production: data analysis, modeling, evaluation, offline/online A/B testing, and iterative improvement
- Collaborate cross-functionally with engineers, PMs, data scientists, and designers to ensure our AI drives meaningful product improvements
- Stay at the forefront of ML/AI innovation by evaluating and incorporating emerging research and algorithms into the product lifecycle

## Preferred Qualifications
- 5+ years experience building and shipping robust ML/AI models for large-scale, user-facing or data-driven products
- Deep expertise in deep learning (**PyTorch**, **TensorFlow**, **JAX**), LLMs, information retrieval, content summarization, recommendation systems, NLP, and/or ranking
- Strong software engineering skills (**Python**, production-quality codebases, collaborative development)
- In-depth experience with the full ML lifecycle: data analysis, feature engineering, iterative model development, rigorous evaluation, and ongoing monitoring/improvement
- Proven collaborator and communicator; excels in high-velocity, cross-functional teams
- Curious, driven by end-user/product impact, and passionate about advancing the state of applied ML and AI
- BS, MS, or PhD in Computer Science, Engineering, or related field (or equivalent experience)

## Bonus Points For
- Experience with LLM prompt engineering, Retrieval-augmented generation (**RAG**) based systems
- Experience in large scale user-centric and content-centric personalization challenges (user modeling, retrieval, content ranking, etc)
- Open-source or published contributions in ML, NLP, IR, or relevant research fields

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**Apply:** https://hotfix.jobs/jobs/fa2a14c5-a9f8-41ed-b414-a6dc50f0126d
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