Senior Full Stack Developer

React / Next.js · Node.js · Headless Commerce

Company: 99Commerce Limited

Location: Remote (Worldwide)

Type: Full-Time Contractor

About 99Commerce

99Commerce is a DTC brand-building company behind a growing portfolio of e-commerce brands — including health wearables, pet products, and maternity. We move fast, build lean, and use the best tools available, including AI, to punch above our weight.

You'll be the lead full stack developer on a small but fast-moving team. Real ownership, real impact.

The Role

We're hiring a Senior Full Stack Developer to own both frontend architecture and backend systems across our brand storefronts and internal tooling. You'll lead headless Shopify builds, design and maintain the backend and API layer, and ship features across multiple live DTC brands. This is a hands-on engineering role, you write code, design systems, and own outcomes end-to-end.

What You'll Do

Frontend Systems

• Architect and build high-performance storefronts using React and Next.js
• Define rendering strategies (SSR, SSG, ISR, Edge) based on product and SEO requirements
• Optimise Core Web Vitals and real-world performance across critical user flows — PDP, PLP, checkout
• Build scalable UI systems: design systems, reusable components, and state architecture
• Own frontend performance, accessibility, and cross-device compatibility

Backend & API Layer

• Design and implement backend services using Next.js API routes, serverless functions, and Node.js-based services where needed
• Build and maintain data orchestration layers — aggregate data from Shopify, CMS, analytics, and third-party systems
• Design and manage GraphQL and REST integrations, including Shopify Admin API, webhooks, and Shopify Functions
• Implement event-driven and webhook-handling workflows
• Own data flow architecture — caching, consistency, and latency tradeoffs
• Integrate third-party services: payments, fulfilment, transactional email (Resend), and CRM/ERP sync

• Design scalable, multi-brand architecture across storefronts and internal tools
• Define abstraction layers between the commerce platform (Shopify), frontend applications, and internal services
• Own caching strategies across CDN, edge functions, and server-side layers
• Ensure system reliability, observability, and debuggability in production
• Integrate and configure monitoring and error tracking (e.g. Sentry)

Engineering Ownership

• Set and enforce engineering standards across the full stack
• Conduct code reviews focused on system design, not just syntax
• Debug complex production issues across frontend, backend, and integrations
• Collaborate with product, design, and brand teams at the level of technical feasibility and tradeoffs — not task execution
• Use AI-assisted development tools as a core, daily part of your workflow

Minimum Requirements

Experience

• 5+ years of professional software engineering experience
• Strong, demonstrable experience across both frontend and backend systems

Frontend

• Expert-level proficiency in React.js and Next.js
• Expert-level JavaScript and TypeScript across large-scale applications
• Solid knowledge of HTML5, CSS3, and Tailwind CSS
• Proven experience building headless commerce storefronts (Shopify Storefront API preferred)
• Deep understanding of SSR, SSG, ISR, hydration, and rendering tradeoffs
• SEO fundamentals and Core Web Vitals optimisation

Backend

• Strong API design experience — both REST and GraphQL, not just consuming them
• Comfortable working serverless and with edge functions; Node.js-based services
• Knowledge in building and managing database schemas — Supabase, PostgreSQL, and similar
• Experience with Redis or similar caching layers (e.g. Upstash)
• Strong understanding of web and app authentication and security best practices
• Experience with Shopify Admin API, webhooks, and Shopify Functions — not just the Storefront API

Infrastructure & Tooling

• Experience deploying and operating systems on Vercel or similar platforms
• Strong Git and GitHub workflows in collaborative engineering environments
• Solid debugging skills across the full stack — client, server, network

• Experience designing multi-brand or multi-tenant architectures
• Experience with GraphQL at scale
• Comfortable with ORMs like Prisma or Drizzle
• Knows background jobs — queues, cron, and event-driven workflows
• Solid testing across the stack: unit, integration, API, and end-to-end (Playwright, Vitest, Jest, or Cypress)
• Integration experience with headless CMS platforms (Sanity, Contentful, etc.)
• Experience designing data pipelines and system integrations
• Experience in DTC or high-performance e-commerce environments
• Familiarity with experimentation systems — A/B testing and CRO tooling

Nice to Have

• 3–5 years of React Native experience — app projects are on our roadmap
• Flutter experience
• Experience with Shopify Hydrogen / Oxygen
• Familiarity with backend frameworks such as Express, NestJS, or Fastify
• CI/CD pipeline setup and management
• Background in DTC, e-commerce, or multi-brand environments

AI Tooling Is Not Optional

We use AI-assisted tools across the entire business. For this role, we expect you to actively use tools like Claude Code, Cursor, GitHub Copilot, or Codex CLI as part of your daily workflow. Comfort with MCP server integrations and agentic development workflows is a genuine plus — not a checkbox.

What We Offer

• Competitive pay depending on experience and location
• Fully remote and async-friendly team
• Work across multiple DTC brands — varied, fast-paced, with real ownership
• Direct access to founders — no layers of bureaucracy

To apply, send your CV, portfolio or GitHub, and a short note on your headless Shopify and backend experience.