Senior Software Engineer, Frontend – AI Platform

We are currently seeking a Senior Frontend Software Engineer to join the AI Platform team, Addepar’s next-generation AI platform that enables seamless insights and interaction through natural language and data intelligence across our AI products. As a Senior Frontend Engineer, you’ll design and scale the interactive surface of AI Platform products. You’ll work at the intersection of AI, design, and systems engineering, building a class of real-time AI experiences for users — where every frame, token, and scroll behavior matters. You will collaborate closely with product design, backend, and AI/ML engineers to deliver smooth, trustworthy AI experiences that align with Addepar’s standards of performance, transparency, and reliability.

Responsibilities

Design and implement complex, real-time UI features for conversational interfaces, including chat streaming, incremental rendering, and dynamic layouts; Build high-performance WebSocket pipelines to handle streamed deltas, retries, and backpressure gracefully; Optimize scrolling and rendering performance using requestAnimationFrame, virtualization, intersection observers, and non-blocking state updates; Implement fault-tolerant UI logic for reconnection, cancellation, offline recovery, and retry without user disruption; Architect state management and caching strategies to maintain consistency between local UI and backend deltas; Collaborate with designers to deliver accessible, responsive, and pixel-perfect interfaces across themes and viewport sizes; Extend Addepar’s frontend developer experience by refining the build pipeline, test automation, and linting/formatting standards; Instrument client-side telemetry and performance metrics to measure render latency, streaming lag, and user interaction speed; Mentor teammates through design reviews and pair programming, contributing to shared components and cross-product standards; Work closely with backend and AI/ML teams to co-design message formats, token streaming APIs, and session-level resiliency mechanisms; Shape the technical direction of AI Platform’s frontend, contributing to shared libraries and caching strategies

Requirements

Bachelor’s degree in Computer Science, Engineering, or related technical field (or equivalent practical experience); At least 5 years of professional frontend development experience in a production environment; Strong proficiency in TypeScript/JavaScript and deep understanding of asynchronous browser behavior; Experience with Svelte, React, or another component-based modern UI framework; Strong debugging and performance profiling skills; Experience integrating real-time or streaming data into user interfaces; Strong communication, collaboration, and mentoring skills; Legal authorization to work in the country where this role is based (visa sponsorship is not available); Deep understanding of the browser’s rendering pipeline (DOM, CSSOM, layout, paint, compositing); Ability to identify and fix layout thrashing, paint storms, and jank through Chrome DevTools performance profiling; Knowledge of animation scheduling via requestAnimationFrame, idle callbacks, and microtask queues; Familiarity with modern web APIs such as IntersectionObserver, ResizeObserver, MutationObserver, OffscreenCanvas, Web Workers, and BroadcastChannel; Strong command of Promises, async/await, generators, and cancellation (AbortController); Familiarity with streaming data protocols (e.g., WebSockets, SSE) and patterns like batching, throttling, and debounce; Understanding of backpressure and how to pace UI rendering vs. message ingress; Experience designing immutable data flows with fine-grained updates (diffs, patches, deltas); Knowledge of caching, reconciliation, and hash-based change detection; Practices for ensuring consistency between transient client state and authoritative backend models; Familiarity with reactive component frameworks (Svelte preferred, React/Vue acceptable); Experience isolating side effects, using stores/signals, and maintaining predictable reactivity graphs; Ability to decompose large applications into feature modules with lazy loading, error boundaries, and shared design tokens; Ability to evaluate and integrate across frameworks (Svelte, React, Web Components) while maintaining consistent patterns in state, testing, and accessibility; Proven skill in measuring and optimizing UI latency (first paint, input delay, FPS stability); Comfort with Chrome Performance, Lighthouse, or custom performance markers; Experience building virtualized views (infinite scroll, chat lists, large tables); Experience building and maintaining reusable design systems with Storybook, Tailwind, or Web Components; Knowledge of accessibility standards (WCAG, ARIA) and best practices for keyboard, color, and screen reader support; Skilled at collaborating with design teams to translate high-fidelity Figma specs into performant, production-ready components; Writes defensive code to handle partial data, dropped connections, race conditions, and AbortErrors; Understands test pyramids (unit, integration, and end-to-end with Playwright, Jest, Vitest); Adds telemetry hooks and log events to diagnose production issues and user experience regressions; Comfortable configuring bundlers (Vite, Webpack) and optimizing build times; Sets up linting, type checking, and pre-commit automation for consistency; Experience with CI/CD, incremental testing, and feature flag rollouts; Experience with AI-assisted developer tools or scripting build/test automation to improve team velocity; Thinks in systems, not pages; Balances aesthetics with performance, correctness, and maintainability; Enjoys teaching others, debugging difficult issues, and making the team move faster through better abstractions

Nice to have

Svelte (preferred); Familiarity with AI/LLM-powered interfaces; Progressive streaming UIs; Data-rich visualization frameworks