Principal UI Engineer: AI DevTools & Real-Time Platform

Yahoo; Uz; Hybrid; EUR 128,000 - 266,000; Full time

Benefits offered by this job

Flexible hybrid work options

Healthcare

401k

Backup childcare

Education stipends

Job summary

Yahoo seeks a seasoned Principal Engineer to own the platform architecture behind our real-time collaboration services. You will optimize CRDT-based multi-user editing, ensure durable state, and design AI-ready tooling that safely inspects and changes design systems and codebases.

You will lead performance tuning, CI/CD improvements, and secure access controls while mentoring engineers and guiding cross-functional stakeholders toward scalable, resilient solutions.

Qualifications

• 8+ years designing production-scale web platforms.
• Advanced mastery of TypeScript, JavaScript, React, and server-side runtimes (Node.js/Bun).
• Hands-on experience with real-time data models, WebSockets, and CRDTs (Yjs/Automerge) or OT.
• Strong PostgreSQL foundations and schema evolution.
• Experience diagnosing browser and server performance issues using profilers and tracing.
• Experience with cloud, containerized services, and CI pipelines.
• Daily use of AI coding agents for code generation, refactoring, and testing.
• Clear technical communication and leadership in architecture decisions.

Responsibilities

• Own architecture, scalability, and uptime of real-time collaboration server and persistence layer.
• Design, harden, and evolve multi-user editing with CRDTs ensuring durability and conflict handling.
• Architect agent interfaces and Model Context Protocol (MCP) servers for AI tooling.
• Profile and optimize end-to-end performance of interactive canvas and server workloads.
• Lead monorepo operations, CI/CD pipelines, testing, and environment management.
• Define SLOs, metrics, logging, and incident response; drive durable fixes.
• Ensure access control across systems, branches, and files.
• Mentor engineers and drive architectural governance through reviews.

Skills

TypeScript

JavaScript

React

Node.js

WebSockets

CRDTs

PostgreSQL

Performance debugging

AI tooling

Tools

Yjs

Automerge

WebSocket

Redis

CI/CD

Job description

Yahoo seeks a seasoned Principal Engineer to own the platform architecture behind our real-time collaboration services. You will optimize CRDT-based multi-user editing, ensure durable state, and design AI-ready tooling that safely inspects and changes design systems and codebases.

You will lead performance tuning, CI/CD improvements, and secure access controls while mentoring engineers and guiding cross-functional stakeholders toward scalable, resilient solutions.