Role Purpose

SLTWTR is seeking a Senior Frontend Engineer with deep JavaScript expertise to craft rich, high-performance front-end experiences for our eCommerce clients. This role is for someone who writes vanilla JavaScript like it’s a second language; able to build complex interactions, components, and controllers from scratch without reaching for a framework.

You’ll work closely with designers, product owners, and backend engineers to bring high-touch brand experiences to life, often inside customized Shopify environments, and always with performance, reusability, and precision in mind.

Reports To

• Primary: Operations Lead
• In Sprint: Delivery Lead / Product Owner

Core Responsibilities

This seat holds accountability for:

1. Custom JavaScript Development: Architect and implement complex frontend logic and UI behavior using vanilla JavaScript and minimal dependencies.
2. Component & Controller Engineering: Build reusable, modular frontend systems, like cart logic, dynamic filtering, modal systems, and other UX components, with clean structure and performance in mind.
3. Shopify Frontend Implementation: Execute highly customized theme development using Liquid, metafields, Shopify’s APIs, and peripheral APIs where necessary.
4. Shopify Checkout & Customer Account Extensions: Develop and maintain frontend-focused extensions to elevate the customer experience and satisfy specific client requirements.
5. Sprint Collaboration & Delivery: Collaborate with Product Owners and designers to scope features, plan UI states, and ensure stories are accurately estimated and executed.
6. Code Quality & Frontend Consistency: Ensure readable, well-documented code.

Qualifications

We are looking for candidates who demonstrate proficiency in the following key areas:

Required "Must-Have" Expertise

• 5+ years of hands-on, professional front-end development experience.
• Comfortable working independently in a remote, sprint-based environment
• Deep Vanilla JavaScript Expertise: Proven experience building complex UI logic without reliance on heavy frameworks (e.g., Vue, React).
• Shopify Platform Mastery:
• Expert-level experience with Liquid for theme and template development.
• Proven experience building Shopify Checkout UI Extensions and other platform extensions (e.g., App Blocks).
• Strong understanding of Shopify architectural best practices to deliver scalable and maintainable solutions, including the ability to consult and support technical colleagues.
• Component Engineering: Extensive experience designing and implementing highly reusable, modular UI systems using Web Components (or similar framework-agnostic standards).
• Styling & Performance:
• Proficiency with modern CSS and preprocessors, with hands-on experience using utility-first frameworks like Tailwind CSS.
• Strong understanding of browser APIs, event handling, state management, and performance profiling tools (Lighthouse, Chrome DevTools).

Additional Qualifications

• Experience with the Shopify Storefront API and best practices for integrating headless or hybrid architectures.
• Familiarity with the Shopify CLI and version control workflows.
• Comfortable working independently in a remote, sprint-based environment.
• A portfolio demonstrating high-performance, complex frontend solutions.