← All roles

Member of Technical Staff (Machine Learning Engineer, Search Agent RL)

Perplexity· Search
Apply on company site
Hybrid (Belgrade), Hybrid (London), Hybrid (Berlin)Full-timePosted 2w ago

About the role

Machine Learning Engineer focused on advancing search, reasoning, and multi-agent systems for Perplexity, spanning model training, agent harnesses, and retrieval infrastructure.

Responsibilities

  • Push search and agent quality forward through improvements to models, training data, tools, and system design.
  • Develop LLM post-training methods, including reinforcement learning, to improve reasoning, search, tool use, and task completion.
  • Train and evaluate multi-agent systems, exploring how agents divide work, share information, and coordinate effectively.
  • Design and build agent harnesses around the tools, context management, execution environments, and orchestration that support reliable work over many steps.
  • Improve retrieval and ranking models and the search interfaces agents use to find and assess information.
  • Build datasets, reward signals, and evaluations that expose meaningful failures and guide improvements.
  • Own experiments end to end, from a clear hypothesis to scalable training, deployment, and measurable gains in quality, latency, and cost.
  • Collaborate with AI, Search, Infrastructure, Data, and Product teams to bring new capabilities into production.

Qualifications

  • A strong track record of building and shipping ML systems, with deep experience in one or more of LLM post-training, reinforcement learning, search and retrieval, or agent systems.
  • Strong software engineering skills and the ability to work across model training, experimentation infrastructure, and production systems.
  • Experience designing rigorous evaluations, diagnosing failures, and translating experimental results into practical improvements.
  • Comfort with open-ended problems that require both research judgment and hands-on engineering.
  • A strong sense of ownership, curiosity, and the drive to carry an idea through to a working system.

Skills

Required:ML system design and shippingLLM post-training / reinforcement learningSearch and retrieval
Nice to have:Agent systems / multi-agent coordination
Last updated Oct 21, 2026. Interested? Apply on the company site.

About Perplexity

ai-plg-top-20brex-fastest-growing-2025liquid-ai-recruiting-targetsetter-30setter-30-2026-q1
Company profileWebsite

More open roles at Perplexity