Senior Full-Stack Developer (Next.js)

About the role

Ruby Labs is looking for a highly autonomous Senior Full-Stack Developer to build and ship features for a core D2C subscription product. You will own each feature end to end across a TypeScript monorepo: a Next.js App Router client, a Fastify + Payload CMS API on PostgreSQL, and Cloudflare Workers at the edge. The role suits someone who treats production as the standard, works inside the team's Feature-Sliced Design conventions, and communicates risks early in a remote team.

Key responsibilities

• Build features across the Next.js client and the Fastify + Payload CMS backend, following the team's layering, naming and import conventions
• Ship changes behind feature flags and A/B experiments, fully localized across supported locales
• Integrate third-party providers (billing, email/CRM, analytics) via REST APIs and webhooks
• Cover functionality with unit, integration and e2e tests; run a thorough self-review and review teammates' code
• Fix bugs, perform root-cause analysis, and optimize page and endpoint performance (rendering, caching, database queries, bundle size)
• Apply secure development practices (schema validation, access control, safe handling of secrets) and observability practices (structured logging, metrics, alerts)
• Break down, estimate and ship your own tasks within the sprint, and escalate architectural decisions to senior engineers

Required profile

• 2+ years of commercial React experience, including 1+ year with Next.js (App Router, Server Components, route handlers, rendering and caching strategies) and solid TypeScript
• Node.js backend experience on a typed HTTP framework (Fastify, Nest or Express) with PostgreSQL, REST API design, schema migrations and REST/webhook integrations
• Modern client stack: TanStack Query, Zustand, React Hook Form + Zod, Tailwind CSS, and a component library such as HeroUI, MUI or shadcn/ui
• Experience with a code-first headless CMS on PostgreSQL (Payload, Strapi, Directus or equivalent)
• E2e tests (Cypress or Playwright) and unit/integration tests (Vitest or Jest), Git flow, code review, and daily use of AI development tools with full ownership of generated code
• English at B1+ level; applicants must live within about +/- 4 hours of CET

What we offer

• Remote work environment
• Unlimited paid time off and paid national holidays
• Company-provided MacBooks
• Flexible independent contractor agreement with tax advantages and networking opportunities