Member of Technical Staff (Machine Learning Research Engineer)

Perplexity is seeking an experienced Machine Learning Research Engineer to help build the next generation of advanced search technologies, with a focus on retrieval and ranking.
Responsibilities
Relentlessly push search quality forward — through models, data, tools, or any other leverage available

Architect and build core components of the search platform and model stack

Design, train, and optimize large-scale deep learning models using frameworks like PyTorch, leveraging distributed training (e.g., PyTorch Distributed, DeepSpeed, FSDP) and hardware acceleration, with a focus on retrieval and ranking models

Conduct advanced research in representation learning, including contrastive learning, multilingual, and multimodal modeling for search and retrieval

Deploy models — from boosting algorithms to LLMs — in a scalable and performant way

Build and optimize RAG pipelines for grounding and answer generation

Collaborate with Data, AI, Infrastructure, and Product teams to ensure fast and high-quality delivery

Qualifications
Deep understanding of search and retrieval systems, including quality evaluation principles and metrics

Proven track record with large-scale search or recommender systems

Strong proficiency with PyTorch, including experience in distributed training techniques and performance optimization for large models

Expertise in representation learning, including contrastive learning and embedding space alignment for multilingual and multimodal applications

Strong publication record in AI/ML conferences or workshops (e.g., NeurIPS, ICML, ICLR, ACL, CVPR, SIGIR)

Self-driven, with a strong sense of ownership and execution

Minimum of 3 years (preferably 5+) working on search, recommender systems, or closely related research areas