Principal Engineer Frontend

Overview

PENNYMAC

Pennymac (NYSE: PFSI) is a specialty financial services firm with a comprehensive mortgage platform and integrated business focused on the production and servicing of U.S. mortgage loans and the management of investments related to the U.S. mortgage market.

At Pennymac, our people are the foundation of our success and at the heart of our dynamic work culture. Together, we work towards a unified goal of helping millions of Americans achieve aspirations of home ownership through the complete mortgage journey.

As a Principal Frontend Engineer on the AI Platform Services team, you will be the architect of the platform's "face" and the guardian of the user experience. While the backend team builds the "brain" (RAG pipelines and autonomous agents), you will build the "Collaborative Canvas"—the interface where human ingenuity meets artificial intelligence.

You will not just be building standard dashboards; you will be engineering complex,
AI-native interfaces that rival commercial tools like Cursor and Linear. You will solve unique challenges in Generative UI
, real-time state synchronization, and browser-based code editing. You will define how our engineers interact with autonomous agents, moving beyond simple "chatbots" to build a deeply integrated, multi-modal workspace that feels like a natural extension of the person's mind.

This role requires a unique blend of elite frontend engineering, a deep understanding of developer tooling (IDEs, CI/CD interfaces), and a visionary approach to Human-Computer Interaction (HCI) in the age of AI.

• Chart Pennymac’s AI Course: This is a greenfield opportunity to join a foundational team and build a transformative platform from the ground up, with the stability and resources of an industry leader.
• Define the AI Interface: This is an opportunity to invent new UI patterns for "Agentic Workflows." You will move beyond static forms to build interfaces that generate themselves based on user intent and AI context.
• High-Impact & Visibility: Nexus is a top-priority strategic initiative. Your work will be the primary touchpoint for senior leadership and hundreds of engineers, directly impacting the "Idea-to-Production" velocity of the entire organization.
• Solve Unique Problems: You will tackle cutting-edge challenges in Collaborative Editing (CRDTs),
  Streaming UI
  , and Visualizing Complex Agent Reasoning
  —problems that sit at the bleeding edge of modern web development.
• Competitive Compensation: We offer a competitive salary, bonus, and benefits package, including comprehensive health/dental/vision plans, 401(k) matching, and more.
• Career Growth: We are committed to the growth of our team members and provide opportunities for continuous learning, professional development, and career advancement within a leading Fin Tech company.

• Architect the Agentic Workspace: Design and build the core frontend architecture for the AI platform using React
  , Type Script , and Next.js
  , ensuring sub-second performance even with heavy data visualization and real-time streams.
• Build the "Collaborative Canvas": Engineer a real-time, multi-player workspace where AI agents and humans can co-author artifacts (User Stories, PRDs, Architecture Diagrams). Implement CRDTs (Conflict-Free Replicated Data Types) and Web Socket infrastructures to manage shared state seamlessly without data loss.
• Master the "Generative UI": Develop a robust component registry and rendering engine that allows AI agents to dynamically generate interactive UI elements (charts, forms, checklists) on the fly, rather than just outputting text.
• Visualize Intelligence: Create intuitive visualizations for the "Unified Context Library," allowing users to see why an AI agent made a decision, trace its sources (Jira, Confluence, Git Lab), and inspect its reasoning graph via interactive diagrams.
• Partner with the Backend: Collaborate closely with Principal Backend Engineers to define the API contracts (Graph
  
  QL, Streaming JSON, Server-Sent Events) that enable the frontend to consume complex agent outputs efficiently.
• Developer Experience (DX) Leadership: Work directly with your "customers"…