Principal Engineer – AI, Retrieval & Discovery Systems

Pinterest; San Francisco (CA); On-site; USD 243,000 - 450,000; Full time

Job summary

Pinterest is seeking a Principal Engineer to set the technical vision and lead foundational work across Homefeed, Search, and AI Assistant. This role defines long‑term architecture, raises the bar for ML and systems excellence, and partners with product and executive leadership to drive durable improvements in engagement and creator value.

You will act as a cross‑cutting technical leader, combining hands‑on design with strategy, mentoring senior engineers and driving multi‑team alignment to

Qualifications

• 15+ years of experience in large-scale systems and/or ML.
• Proven experience as a Principal Engineer, Architect, or equivalent senior technical leader.
• Deep expertise in retrieval and ranking, representation learning, search systems, or large language models and generative AI.
• Ability to define and drive multi-year architectural transformations at scale.
• Strong product intuition and collaboration with PM/Design/Data Science on ambiguous bets.
• Bachelor’s degree in CS or related field or equivalent experience.

Responsibilities

• Define long-term technical strategy and architecture for Homefeed, Search, and AI Assistant.
• Drive a multi-year roadmap for unified signals, features, and models.
• Lead design of large-scale retrieval and ranking systems to improve relevance and monetization.
• Architect integration of LLMs with core discovery stack and safety controls.
• Set experimentation and evaluation frameworks for ML and discovery use cases.
• Provide hands-on technical leadership on high-leverage projects and mentor engineers.
• Partner with Product, Data Science, Research, and Design to align problems with robust technical plans.
• Raise engineering standards for reliability, performance, and security.

Skills

Large-scale systems

Machine learning

Architectural leadership

Cross-functional collaboration

Product strategy

Mentoring engineers

Executive communication

Education

Bachelor’s degree in Computer Science

Tools

TensorFlow / PyTorch

Distributed systems tooling

Job description

Pinterest is seeking a Principal Engineer to set the technical vision and lead foundational work across Homefeed, Search, and AI Assistant. This role defines long‑term architecture, raises the bar for ML and systems excellence, and partners with product and executive leadership to drive durable improvements in engagement and creator value.

You will act as a cross‑cutting technical leader, combining hands‑on design with strategy, mentoring senior engineers and driving multi‑team alignment to