Senior Frontend Engineer (Widget Runtime)

About the role

The Idukki widget runtime is the single biggest piece of code in our customer-facing surface area. It runs on every PDP, PLP, lookbook, story rail and email tile across thousands of brand storefronts. You own its weight, its rendering performance, its accessibility, and the API the rest of the team builds on top of.

What you'll do

• Hold the line on the 37 KB gzipped budget, every new feature gets weighed against impressions
• Drive Core Web Vitals on every customer site: keep CLS < 0.001, INP < 200ms, LCP impact < 50ms
• Build the public widget SDK + storybook + visual-regression harness that the AI/ML and product teams ship against
• Own A11y conformance (WCAG 2.2 AA) and i18n across 10 European + 4 APAC locales
• Run our experimentation framework: variant injection, sticky bucketing, server-side fallback
• Mentor 2-3 engineers; participate in hiring loops

What you'll need

• 6+ years shipping production JavaScript/TypeScript with a deep React + Web Components background
• Demonstrable runtime-performance wins on a high-traffic surface (case study or shipped repo)
• Hands-on with Vite, esbuild, rollup tree-shaking + module-federation tradeoffs
• Has owned an a11y conformance audit end-to-end
• Comfort working async with a globally distributed team

Nice to haves

• Shopify theme + Liquid + checkout-extensibility familiarity
• Prior work on a CDN-distributed JS SDK
• Experience with edge-rendered React (Cloudflare Workers, Fastly Compute)