Liam O'Sullivan Senior Svelte Developer
Toronto, Canada • sveltedev@gmail.com • +1 (416) 555-0148
Profile Summary
- Senior Svelte Developer with 7 years of experience building small-bundle Svelte applications at scale across developer dashboards, security tooling, and content-heavy product surfaces, specializing in Svelte 5 runes, SvelteKit load functions, and edge-adapter delivery.
- Hands-on coverage across Svelte versions (Svelte 5, SvelteKit), reactivity (runes, Svelte stores), UI and styling (Skeleton, Tailwind CSS), testing (Vitest, Playwright), and languages (TypeScript, JavaScript) with strong fundamentals in compile-time reactivity, small-bundle discipline, and hydration-aware rendering.
- Deep expertise in runes-based reactivity, SvelteKit load and form actions, edge-adapter delivery, and type-safe component delivery, leveraging methodologies such as compile-time reactivity and no-VDOM rendering and progressive enhancement and server-first load patterns to drive fast, accessible, type-safe Svelte applications fit for modern product teams.
- Engaged collaborator working cross-functionally with Product, Design, Backend, and Platform teams in Scrum and Kanban delivery environments, contributing to architecture forums, sprint planning, and design reviews with an ownership-first mindset and clean handoffs.
- Emerging leader who shares technical excellence and fosters a culture of component reusability and accessibility discipline through PR reviews and pattern docs, while leading Svelte guild and design-system review sessions and authoring widely used component and store templates.
Technical Skills
- Svelte & Frameworks:
- Svelte 5, Svelte 4, .svelte components, script setup, SvelteKit, Astro + Svelte, VitePress
- Reactivity & Runes:
- $state, $derived, $effect, $props, $bindable, reactive statements ($:), tick, untrack
- State Management:
- Svelte stores (writable, readable, derived), context API, runes-based state, store composition
- UI & Styling:
- Skeleton, Flowbite Svelte, shadcn-svelte, Melt UI, Bits UI, Tailwind CSS, UnoCSS, scoped CSS
- TypeScript & Tooling:
- TypeScript (strict), svelte-check, ESLint, Prettier, Vite, esbuild, Rollup, pnpm
- Testing:
- Vitest, Svelte Testing Library, Jest, Playwright, Cypress, MSW, Storybook, Histoire
- Performance & Build:
- Vite HMR, no-VDOM rendering, code splitting, prefetching, edge adapters, LCP/INP, tree shaking
- Accessibility & Routing:
- SvelteKit file-based routing, nested layouts, route groups, hooks, WCAG 2.2, ARIA patterns, semantic HTML
Education
University of
Waterloo
B.S. in Computer
Science
Work Experience
1Password
Senior Svelte
Developer
- Drove Svelte application development and end-to-end feature delivery across 1Password web vault and admin console supporting 6 product squads, shipping item management flows, team admin dashboards, and secret sharing surfaces across 55+ lazy-loaded routes.
- Owned SvelteKit full-stack delivery with load functions and form actions, server routes, hooks.server, and route groups on the Cloudflare adapter across 40+ server endpoints, cutting hydration-mismatch incidents per quarter on the vault by 72%.
- Built reactivity with Svelte 5 runes including $state, $derived, and $effect for component state, derived values, and side effects, plus $props and $bindable for clean parent-child contracts, migrating 120+ components off reactive statements across 6 squads.
- Architected client state with writable and derived stores for cross-feature global state, context API for scoped contexts, and runes-based local state inside components across 18 stores, retiring 5+ classes of stale-state and double-mutation bugs.
- Owned TypeScript adoption and type-safe Svelte through typed $props and load function returns with svelte-check on the CI path in strict-mode TypeScript, lifting strict coverage from 58% to 96% and cutting runtime error incidents by 64%.
- Drove performance and build tooling with route-level code splitting and prefetching, Vite-powered HMR, tree-shaken Rollup builds, and Svelte's no-VDOM runtime, pulling initial bundle from 1.4MB to 340KB and LCP from 2.8s to 1.1s on the vault home.
- Built API integration with server load functions for typed REST calls, form actions for progressive-enhancement mutations, and request caching, plus OIDC and session refresh and GraphQL queries via Houdini across 80+ REST and GraphQL endpoints, dropping failed-call rates by 46%.
Shopify
Svelte
Developer
- Built SvelteKit routing and navigation with file-based routing with nested layouts, route groups for merchant and partner spaces, dynamic routes, and hooks for authenticated areas across 50+ routes, cutting initial load on the storefront editor by 52%.
- Designed component architecture with single-file .svelte components, slots and snippets for layout composition, transitions and animations, and dynamic components for modals and drawers, shipping 130+ reusable components adopted across merchant and partner surfaces.
- Owned styling and UI implementation with Tailwind CSS with scoped component styles, CSS variables for theming, and a shared token system mapping the design library to .svelte components, shipping 150+ design tokens across web and mobile-web surfaces.
- Owned Svelte testing with Svelte Testing Library with Vitest and Playwright for end-to-end coverage on merchant onboarding, lifting unit coverage from 44% to 84%, cutting regression escapes per release by 60%, and onboarding 3 junior Svelte developers.