Principal UI Engineer for AI-Driven Dev Tools

Yahoo Holdings Inc.; Mountain View (CA); Hybrid; USD 144,000 - 299,000; Full time

Job summary

Yahoo Holdings Inc. is seeking a seasoned Principal Engineer to own the real-time collaboration platform, CRDT-based multi-user editing, and a scalable Postgres-backed persistence layer. You will mentor engineers, shape architecture, and drive performance across frontend and backend systems.

You will guide AI tooling, develop agent interfaces, and optimize UI rendering, while ensuring reliability, security, and efficient CI/CD practices across a hybrid, flexible work model.

Qualifications

• 8+ years of experience designing, building, and operating production-scale web platforms.
• Advanced mastery of modern TypeScript, JavaScript, React, and server-side runtimes (Node.js or Bun).
• Hands-on experience with real-time data models, WebSockets, and collaborative editing (CRDTs such as Yjs or Automerge, or OT), with a solid grasp of consistency, concurrency, and failure modes.
• Strong SQL and relational database (PostgreSQL) foundations, including schema evolution and access-control patterns.
• A track record of diagnosing and resolving complex performance issues in the browser (rendering, Web Vitals, memory) and on the server (latency, throughput, resource usage).
• Experience running production services: metrics, alerting, structured logging, on-call, and designing for graceful degradation.
• Experience with cloud and serverless deployment platforms, containerized services, CI pipelines, and multiple environments (preview, staging, production).
• Daily, productive use of AI coding agents and LLM-based CLI tooling for code generation, refactoring, and test authoring.
• Clear technical communication and proven leadership in driving architectural consensus across engineering, design systems, and product stakeholders.

Responsibilities

• Platform Architecture & Core Infrastructure: Own the architecture, scalability, and uptime of our real-time collaboration server, Postgres-backed persistence layer, background jobs, and the APIs that sit on top of them.
• Collaborative Systems & Data Integrity: Design, harden, and evolve multi-user editing built on CRDTs (Yjs). Guarantee reliable sync, reconnection, conflict handling, undo/redo, and save durability, so users' work is never silently lost across disconnects, deploys, or branch switches.
• AI-Augmented Developer Tooling & Agent Interfaces: Architect and maintain agent-ready interfaces, Model Context Protocol (MCP) servers, and automated pipelines that let AI coding agents and developers safely inspect, generate, and change design systems and codebases.
• Performance & Canvas Engineering: Profile and optimize end-to-end bottlenecks: interactive canvas rendering, frame rates, hydration and bundle payloads, query cost, memory footprint, and server event-loop health.
• Developer Infrastructure & Monorepo Operations: Steer the evolution of our large TypeScript monorepo, CI/CD pipelines, automated testing, and preview, staging, and production environments so shipping stays fast, reproducible, and safe.
• Observability & Systemic Resilience: Define SLOs, metrics, structured logging, and real-time alerting. Champion incident management, lead blameless post-incident reviews, and turn root causes into durable, platform-level fixes.
• Security & Access Control: Partner on authentication, authorization, and permission models across systems, branches, and files, so access rules are enforced consistently everywhere.
• UI Engineering: Contribute to product UI in React and TypeScript, especially where performance, state management, and data flow matter most.
• AI Workflow Leadership & Quality: Set standards for using AI coding agents across the software lifecycle, backed by rigorous review, static analysis, and testing that validate AI-assisted output for accuracy, security, and maintainability.
• Technical Mentorship & Governance: Set engineering standards for reliability, code hygiene, and accessibility. Mentor staff and senior engineers, lead high-impact architecture reviews, and align engineering, product, and design roadmaps.

Skills

TypeScript

React

WebSockets

CRDTs

Performance profiling

CI/CD

JavaScript

Server-side runtimes

Technical leadership

Tools

PostgreSQL

Yjs

Automerge

WebSocket servers

Job description

Yahoo Holdings Inc. is seeking a seasoned Principal Engineer to own the real-time collaboration platform, CRDT-based multi-user editing, and a scalable Postgres-backed persistence layer. You will mentor engineers, shape architecture, and drive performance across frontend and backend systems.

You will guide AI tooling, develop agent interfaces, and optimize UI rendering, while ensuring reliability, security, and efficient CI/CD practices across a hybrid, flexible work model.