Principal Software Engineer - UI

What you get to do in this role:
Platform Architecture & Strategy — Define and own the long-term architecture of a server-rendered web component platform that powers AI-native user experiences across the product. You'll make the key decisions on rendering, component runtime, design systems, and streaming UX for AI-generated content, and keep the experience layer resilient and coherent as the platform scales.
Rendering & Performance — Own end-to-end experience performance: server-side rendering, streaming HTML, hydration correctness, and time-to-interactive. Push the state of the art in server rendering of web components so experiences are fast, deterministic, and consistent between server and client.
AI-Native Intelligent Experiences — Build the platform primitives product teams use to expose agentic backends to end users, including recommendations, autonomous triage, generated insights, and multi-step agent reasoning. Own the hard UX problems specific to AI-native products: streaming model output, progressive disclosure of agent reasoning, graceful handling of latency and uncertainty, and human-in-the-loop review flows that make autonomous behavior legible and controllable.
Secure, Scalable Runtime — Design how the platform runs in production on Kubernetes: sandboxed execution of application code, multi-tenant isolation, secure credential and token propagation, memory and resource budgeting, version-tiered rollouts, and observability for a large Node.js fleet under real traffic.
Developer Platform & Ecosystem — Shape the component model, data-loading and context APIs, design system, tooling, and guardrails that let many teams build applications on the platform. Make the right path the easy path.
Agentic Pipeline Awareness — Work closely with ML and platform teams building agent orchestration and tool-calling infrastructure (multi-agent dispatch, MCP-style tool integration, reasoning traceability). Translate what those backends can do into UX patterns that are usable, safe, and trustworthy.
Business Alignment — Tie platform and experience architecture to business goals, so that engineering velocity, experience quality, and adoption of AI-native features support customer acquisition, retention, and time-to-market.
Hands-on Engineering — Write high-performance, production-grade code across the experience stack (TypeScript, Lit.js / Web Components, Node.js, modern build tooling) and the runtime stack (Kubernetes, containerized services). Debug the hardest problems yourself, from hydration mismatches to memory leaks to intermittent production failures.
Cross-functional Execution — Drive business-critical platform outcomes together with ML, backend platform, SRE, security, UX, and product teams.
Engineering Culture — Mentor senior and staff engineers, lead architecture reviews, raise the bar on testing and reliability, and build a culture of rapid, impact-driven innovation.
Ownership & Initiative — Spot platform and experience gaps before they become problems, propose solutions, align stakeholders, and own execution.
To be successful in this role you have:
15+ years of software engineering experience, focused in frontend or web platform engineering at a high-growth tech company or top-tier AI lab.
Deep expertise in web platform internals: Web Components and Shadow DOM, server-side rendering and hydration, streaming, module loading, and browser performance. Production experience with Lit.js, React, or comparable frameworks, and a clear view of the tradeoffs between them.
Strong server-side JavaScript/TypeScript engineering skills: Node.js, HTTP/2, proxies and streaming, V8 memory behavior, and isolate or worker-based execution models.
Hands-on experience running latency-sensitive services on Kubernetes, including resource management, rollout strategies, Helm, and production observability.
Strong web security fundamentals: session and token handling, egress control, sandboxing of untrusted code, and trust boundaries in multi-tenant systems.
Has shipped intelligent, AI-driven user experiences (not just consumed an LLM API), with strong intuition for how agent and model output should surface to real users.
Hands-on experience with agentic or multi-agent systems from the consumer side.
Understands agent orchestration, tool-calling protocols (MCP or equivalent), and reasoning traceability well enough to design UX and platform primitives around them.
Experience designing frameworks, SDKs, or design systems adopted by many teams, including versioning, backward compatibility, and migration strategy.
A track record of connecting platform and UX decisions to business outcomes such as adoption, retention, and time-to-market, not just technical metrics.
Self-driven with strong ownership: able to identify gaps, propose solutions, align stakeholders, and execute at startup pace.
Good to Have
Prior experience in distributed systems performance and scalability, or in large-scale Node.js fleet operations.
Open-source contributions to major web frameworks, SSR tooling, build systems, design systems, or agent-framework projects.
Experience with enterprise SaaS platforms and their extensibility and customization models.
Prior startup experience working closely with Product and Growth teams in an early-stage environment.

Employment type
Full-time

Work arrangement
Hybrid