Member of Technical Staff (AI Researcher)

Perplexity; Greater London; On-site; GBP 164,000 - 361,000; Full time

Job summary

Perplexity seeks top-tier AI researchers and engineers to advance our AI products and Sonar models, with a focus on scalable training and model deployment.

You will work on Core Research, Agent and Comet Agent teams, translating research into practical, high-performance features for our search and agent experiences.

Qualifications

• Experience with large-scale LLMs and deep learning systems.
• Strong Python and PyTorch programming skills.
• Familiar with post-training techniques and RL methods.

Responsibilities

• Advance SOTA models and post-training techniques across products.
• Scale training pipelines and integrate models into product stack.
• Collaborate with engineering and product teams to improve user experiences.
• Turn research into deployable algorithms and experiments.

Skills

Python

PyTorch

Large-scale LLMs

Deep Learning

Education

Bachelor's in ML/CS

PhD preferred

Tools

Megatron-LM

CUDA

Job description

Perplexity is seeking top-tier AI Research Scientists and Engineers to advance our AI products and capabilities. We're building the future of AI-powered search and agent experiences through our Sonar models, Deep Research Agent, Comet Agent, and Search products. Join us in creating SOTA experiences that handle hundreds of millions of queries and continue to scale rapidly.

Team Structure

Depending on your interests and expertise, you'll work on one of three specialized teams:

• Core Research Team (Horizontal) Focus on generating and improving base models that power all our products. This team works on foundational model capabilities, post-training techniques, building RL infra and infrastructure that benefits the entire organization.
• Agent Products Team (Vertical) Concentrate on fine-tuning and optimizing models for our Deep Research Agent and Labs/Canvas products. This team bridges research and product, ensuring our agent capabilities deliver exceptional user experiences.
• Comet Agent Team (Vertical) Dedicated to developing and enhancing our Comet Agent product. This specialized team focuses on the unique requirements and optimizations needed for Comet's specific use cases.

Responsibilities

Research & Development

• Post-train SOTA LLMs using the latest supervised and reinforcement learning techniques (SFT/DPO/GRPO)
• Leverage our rich query/answer dataset to scale model performance across Sonar, Deep Research, Comet, and Search products
• Stay current with the latest LLM research, especially in model training, optimization, and personalization techniques
• Implement preference optimization and personalization capabilities to enhance user experience
• Invent in-house improvements and optimizations to enhance SOTA models
• Turn research ideas into algorithms and run experiments to launch new models

Infrastructure & Implementation

• Own full-stack data, training, and evaluation pipelines required for model development
• Build robust and effective training frameworks (on top of Megatron/PyTorch) for post-training LLMs
• Implement necessary infrastructure and components to support cutting-edge model training at scale
• Integrate models seamlessly into our product ecosystem

Collaboration

• Work closely with engineering teams to integrate models into Perplexity's product suite
• Collaborate across teams to ensure cohesive AI experiences throughout our platform
• Partner with product teams to understand user needs and translate them into model improvements

Qualifications

Required

• Proven experience with large-scale LLMs and Deep Learning systems
• Strong programming skills in Python/PyTorch; versatility is a plus
• Experience with post-training techniques and reinforcement learning
• Self-starter with a willingness to take ownership of tasks
• Passion for tackling challenging problems
• Minimum 2-6 years of experience on relevant projects (depending on seniority level)

Nice-to-have

• PhD in Machine Learning, AI, Systems, or related areas
• Experience in post-training LLMs with SFT/DPO/GRPO
• C++/CUDA programming skills
• Experience building LLM training frameworks
• Academic publications and research impact
• Experience with agent systems and multi-step reasoning
• Background in personalization and preference learning

Compensation Range: $220K - $485K