Principal Fullstack Engineer

SKLUM; Valencia; Presencial; EUR 90.000 - 120.000; Jornada completa

Ventajas ofrecidas por este puesto de trabajo

Private health insurance from Day 1

Relocation policy

Descripción de la vacante

SKLUM is building a mobile-first fullstack app. You will be a hands-on principal engineer guiding the mobile experience from React Native to backend services, collaborating with backend and data teams to ship features end-to-end.

We value deep React Native expertise, strong backend API design, and experience with web tech (React/Next.js). English fluency and cross‑cultural collaboration are essential.

Formación

• 8+ years of professional software engineering experience in hands-on roles.
• Strong React Native expertise including architecture and production-grade patterns.
• Strong backend skills in designing/building APIs and data flows for mobile apps.
• Experience with React and Next.js for web; ability to contribute across platforms.
• Familiarity with mobile delivery practices and observability.
• Experience with AWS and/or GCP, containers, and modern CI/CD.

Responsabilidades

• Design, build, and ship features end-to-end across the Sklum app (mobile-first).
• Own the mobile experience layer: architecture, navigation, performance, offline behavior, production-grade patterns.
• Extend into backend as needed: build APIs, services, data flows with Backend & Data engineer.
• Collaborate with web frontend (React/Next.js) to ensure cross-platform consistency.

Conocimientos

React Native

Backend API design

Frontend architecture

Cloud architectures (AWS/GCP)

CI/CD and observability

English fluency

Educación

Bachelor's degree in Computer Science or related field

Herramientas

Next.js

TypeScript/JavaScript

Descripción del empleo

Sklum Digital & AI is an agentic-native team: a small, high-leverage group that heavily uses agentic AI workflows to build applications and scale our impact far beyond traditional team sizes. For this role in particular, agentic fluency is essential — you will be expected to use agentic tooling every day to multiply your own output, and to help shape how the team leverages these tools.

We are looking for a Principal Fullstack Engineer to be a major hands‑on builder of the new Sklum app, which we are building from scratch. This is a mobile‑first fullstack role: the primary focus is React Native for mobile, extended with the backend work needed to deliver features end‑to‑end.

This is a primarily hands‑on individual contributor role — you will spend most of your time writing and shipping production code. You will report to the Principal Engineer – Architect and work closely alongside the Principal Software Engineer – Backend & Data and other senior engineers to deliver the app from zero to one.

The team operates across multiple cultures, locations, and time zones, and works asynchronously by default. We are looking for an engineer who thrives in distributed environments and builds strong working relationships across geographies.

What you’ll be doing

Mobile-First Fullstack Engineering

• Design, build, and ship features end‑to‑end across the Sklum app — from the React Native mobile experience to the backend services that power it.
• Own the mobile experience layer: architecture, navigation, state management, performance, offline behavior, and production‑grade patterns in React Native.
• Extend into the backend when needed: build APIs, services, and data flows that support the mobile experience, in close collaboration with the Backend & Data engineer.
• Contribute to the web experience (React / Next.js) where features span platforms, ensuring consistency of behavior and design system across mobile and web.

Quality, Performance, and Craft

• Write production‑grade, well‑tested, observable code; own features end‑to‑end from design through deployment and on‑call.
• Drive performance, reliability, accessibility, and security of the mobile experience.
• Establish and maintain engineering standards for the fullstack work you touch — code quality, testing, CI/CD, observability.

Agentic‑Native Ways of Working

• Use agentic AI workflows as a core part of day‑to‑day engineering — from design and coding to testing, review, and operations — to scale your own output and the team's capacity.
• Contribute to the team's agentic operating model: identify where agents can take on more work, where guardrails are needed, and how to keep quality and security high.
• Set a standard for others by showing what one engineer plus well‑designed agentic workflows can deliver.

Collaboration Across the Team

• Partner closely with the Architect, the Backend & Data engineer, product, design, and other specialists to deliver end‑to‑end capabilities.
• Provide technical mentorship and code review, raising the bar for mobile and fullstack engineering across the team.
• Work effectively across cultures, locations, and time zones in a distributed, asynchronous‑first environment.

What we'd like to see

• 8+ years of professional software engineering experience, with a strong record of shipping production systems in hands‑on roles.
• Deep, hands‑on expertise with React Native — including architecture, performance optimization, native module integration, and production‑grade patterns at scale.
• Strong backend engineering skills — designing and building APIs, services, and data flows that support consumer‑facing mobile apps.
• Working expertise with React and Next.js for web, and the ability to contribute to the web experience when features span platforms.
• Solid understanding of mobile delivery practices: app store release processes, over‑the‑air updates, mobile observability, crash reporting, and A/B testing.
• Proven ability to design and build applications end‑to‑end from scratch, and to extend or integrate with existing in‑house or third‑party systems.
• Experience in e‑commerce, marketplace, retail, or other consumer‑facing digital platforms.
• Familiarity with operational systems that surround a consumer app (ERP, CRM, PIM, CMS) and how they connect to the mobile and backend layer.
• Experience with cloud‑native architectures (AWS and/or GCP), containerization, and modern CI/CD practices.
• Hands‑on experience working in an agentic‑native way — using agentic AI tools (e.g., coding agents, autonomous workflows) as a core part of building software, and a demonstrated ability to scale personal and team output through them.
• Proven ability to collaborate effectively across different cultures, locations, and time zones in a distributed, asynchronous‑first environment.
• Strong written and verbal communication skills; fluency in English is required.
• Working proficiency in Spanish or Chinese is a plus.

Benefits you canenjoy

• Private health insurance from Day 1
• Relocation policy

Why work with us

This role sits at the core of SKLUM's Digital and AI team, directly shaping how supply chain decisions are made. You will build a capability that improves forecast accuracy, optimises inventory and distribution, and enhances operational resilience — work that directly influences cost efficiency, product availability, and the end customer experience.

Join our dream, join the SklumTeam!

At our company, we are firmly committed to guaranteeing equal opportunity for all people in our workplace, building an inclusive and equitable environment. We value each employee for their talents, skills, and contributions, regardless of their race, religion, colour, origin, gender, sexual orientation, age, marital status, or disability.