Middle Full-Stack Developer (Next.js) en España, España

About us

Ruby Labs is a leading tech company that creates and operates innovative consumer products. We offer a diverse range of opportunities across the health, education, and entertainment industries. Our innovative teams are driving the future of consumer-led products, and we're always looking for passionate individuals to join us. Learn more about our story at:

About the role

We are looking for a disciplined, highly autonomous Middle https://jobeax.com/link/Z30sZYC3jcRenVso Developer to build and ship product features for one of our core D2C subscription products. You will own features end to end across a TypeScript monorepo — a https://jobeax.com/link/Z30sZYC3jcRenVso App Router client, a Fastify + Payload CMS API on PostgreSQL, and Cloudflare Workers at the edge — from the moment you receive a task, through breaking it down, estimating, implementing, testing, and observability, to a clean release to production and confirmation that it works for real users.

This is a hands-on engineering role suited for someone who treats production as the standard, not the finish line. Half-tested code, silent failures, and unverified AI-generated output are not acceptable. The codebase is convention-heavy — a layered Feature-Sliced Design structure with strict import rules — and you are expected to work inside those conventions rather than around them. You are accountable for every task you take on and for every area of the product you touch: if it breaks, regresses, or stays half-finished, that is yours to see through. We expect maximum autonomy and real involvement in the product — you work independently within a sprint, communicate risks before they become blockers, and escalate architectural decisions to senior engineers rather than guessing.

Key Responsibilities

Feature Development

• Build features across the https://jobeax.com/link/Z30sZYC3jcRenVso client and the Fastify + Payload CMS backend according to product requirements

• Write code that follows the team's Feature-Sliced Design layering, naming, and import conventions

• Ship changes behind feature flags and A/B experiments, fully localized across every supported locale

• Integrate third-party providers — billing, email/CRM, analytics — over REST APIs and webhooks

Quality & Reliability

• Cover functionality with unit, integration, and e2e tests at the level the team expects

• Run a thorough self-review before code review, and review teammates' code with the same rigour

• Fix bugs and perform root-cause analysis for recurring issues

• Optimize page and endpoint performance — rendering and caching strategy, database queries, bundle size

Security & Observability

• Apply secure development practices: schema validation, access control, safe handling of secrets

• Follow observability practices — structured logging, metrics, and alerts — using existing tooling

Collaboration

• Break down, estimate, and ship your own tasks to production within the sprint — and stay accountable for them after release

• Own the areas of the product you work in: their stability, performance, and follow-up fixes

• Surface requirement clarifications, estimate changes, and risks early and in writing

• Escalate complex architectural decisions and critical risks to senior engineers

Qualifications

Must-Have Experience

• 2+ years of commercial React experience, including 1+ year with https://jobeax.com/link/Z30sZYC3jcRenVso (App Router, Server Components, route handlers, rendering and caching strategies) and solid TypeScript

• https://jobeax.com/link/JSd7UYCSg572jJDY backend experience on a typed framework (Fastify, Nest, or Express) with PostgreSQL — REST API design, schema migrations, integrations over REST and webhooks (signature verification, idempotency, retries) — plus a working understanding of auth mechanisms, and web security fundamentals

• Hands-on with the modern client stack: TanStack Query, Zustand, React Hook Form + Zod, Tailwind CSS, and a React component library such as HeroUI, MUI, or shadcn/ui

• Experience with a code-first headless CMS on PostgreSQL (Payload, Strapi, Directus, or equivalent) — collections, access control, generated types, migrations

• Testing and delivery discipline: e2e tests (Cypress or Playwright) and unit/integration tests (Vitest or Jest), Git flow, code review, working with CI

• Daily use of AI development tools (Claude Code or equivalents), including configuring them for a project — context, instructions, rules, MCP/integrations — with full ownership of the quality, security, and correctness of generated code

• English — B1+

Leadership Attributes

• Owns the outcome — takes a task from requirement to production without waiting to be pushed, and stays accountable for the result and the area it touches

• Maximally autonomous and involved — needs a goal, not step-by-step instructions, and cares how the product performs, not just whether the ticket is closed

• Verifies before trusting — treats AI output, third-party responses, and your own code as unproven until tested

• Structured communicator — surfaces risks, blockers, and estimate changes early, in writing, in a remote team

• Knows the edge of their scope — escalates architectural and security decisions instead of improvising them

• Learns from incidents — fixes the root cause, not just the symptom

Location

Ruby Labs operates within the CET (Central European Time) zone. Applicants from any country are welcome to apply for the position as long as they are located within approximately ± 4 hours of CET. This ensures optimal collaboration and communication during working hours.

Benefits

Discover the perks of being part of our vibrant team! We offer:

• Remote Work Environment: Embrace the freedom to work from anywhere, anytime, promoting a healthy work-life balance.

• Unlimited PTO: Enjoy unlimited paid time off to recharge and prioritize your well-being, without counting days.

• Paid National Holidays: Celebrate and relax on national holidays with paid time off to unwind and recharge.

• Company-provided MacBook: Experience seamless productivity with top-notch Apple MacBooks provided to all employees who need them.

• Flexible Independent Contractor Agreement: Unlock the benefits of flexibility, autonomy, and entrepreneurial opportunities. Benefit from tax advantages, networking opportunities, reduced employment obligations, and the freedom to work from anywhere. Read more about it here:

Be part of our fast-growing team and seize this excellent opportunity for personal and professional growth!

Interview Process

After submitting your application, we conduct a thorough review which typically takes 3 to 5 days, but may occasionally take longer due to the volume of applications received. If we see a potential fit, we proceed with the following steps:

• Recruiter Screening (40 minutes)

• Technical Interview (60 minutes)

Life at Ruby Labs

At Ruby Labs, we move fast, aim high, and expect the same from our team. We’re not here to play small—we’re here to build, grow, and win. That means we look for people who are ambitious, driven, and ready to give their best every single day.

This is a place for individuals who thrive under pressure, embrace challenges, and see opportunity in every obstacle. If you’re hungry to achieve, motivated by impact, and want to grow at the speed of your own ambition, Ruby Labs offers the platform to make it happen.

Here, effort is matched with reward. We recognize those who go all in and deliver results, and we create space for people who want more—more responsibility, more growth, and more success.

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