Senior Design Engineer

About Summation

Summation is building an AI Business Planning Platform for CFOs and finance teams. We combine a real-time modeling layer with Addison, our AI calculation engine, to turn messy enterprise data into decision-grade insights. Customers use Summation to model scenarios, explain variances, and automate weekly and monthly reviews.

The Role

Design Engineering at Summation lives at the intersection of product design and frontend engineering. As a Senior Design Engineer, you will ship beautiful, high-performance product experiences in production code, lead our design system, prototype new interactions, and raise the bar on accessibility, motion, and polish. You will partner closely with Product, Design, and Engineering, moving from Figma to code to shipped features.

Roles & Responsibilities

Build production UI in React and TypeScript for Summation’s web app

Lead the Summation Design System: tokens, components, theming, accessibility, docs, and release workflow

Prototype end-to-end product ideas in code, validate with real data, and graduate winners into production

Craft motion and micro-interactions that clarify meaning and reduce cognitive load

Translate flows and states from Figma into resilient, testable components with strong state management

Drive UI performance: bundle hygiene, code-split plans, rendering strategy, perceived latency

Partner with data visualization to express complex financial concepts with clarity

Establish guardrails: lint rules, Storybook checks, accessibility checks, visual regression in CI

Mentor engineers and designers on interaction patterns, system thinking, and front-of-frontend craft

Contribute to product quality across the stack through reviews, pairing, and high-signal documentation

You will love this role if you

Love working across design and code, and care about the details users feel

Think in systems: tokens, states, variants, docs, upgrade paths

Prototype ideas fast and are comfortable deleting code after an experiment

Believe accessibility, performance, and clarity are product features

Enjoy collaborating with PMs, designers, and backend engineers in a high-context startup

Required experience

4+ years building production web UI with React and TypeScript

Strong CSS fundamentals: layout, fluid type and spacing, responsive systems, motion

Design system experience: tokens, component architecture, Storybook, documentation

Data visualization in production using one of Recharts, D3, Visx, ECharts, or similar

Accessibility and quality: semantic HTML, WCAG basics, keyboard and screen reader support, automated checks

Figma fluency: components, variants, auto-layout, dev mode, and handoff

Proven ability to take a concept from Figma to shipped code without heavy PM overhead

Nice to have

Remix or Next.js, Tailwind, shadcn/ui

Framer Motion for interaction design

WebGL or Canvas experience for advanced interactions

Visual regression and accessibility tooling in CI

Experience in fintech, analytics, or complex data products