Principal FullStack Engineer

Experis; España; Remote; PHP 4,982,000 - 7,829,000; Full time

Benefits offered by this job

Full-time remote (CET overlap)

Competitive salary

Claude Team Enterprise access

Direct influence on technical choices

Product used by thousands of merchants

Job summary

Experis is seeking a hands-on senior full-stack engineer to join a lean team of engineers, a designer, and founders. You will own features end-to-end across Next.js frontend, Node.js backend, PostgreSQL, and deployment, shipping with real-time analytics dashboards and a UI component library.

You will work directly with founders, shape technical direction, and raise the bar across the product while collaborating in a small team, comfortable with ambiguity and delivering pragmatic, shipped

Qualifications

• Own a product end to end with depth and ownership.
• Strong TypeScript on frontend and backend.
• PostgreSQL schema design and performance focus.
• Experience maintaining a component library or design system.
• Able to ship pragmatic solutions with limited specs.

Responsibilities

• End-to-end feature delivery across the stack: Next.js frontend, Node.js backend, PostgreSQL, deployment.
• Own real-time analytics dashboard and provide single-view analytics across channels.
• Maintain frontend consistency via UI component library.
• Shape technical direction with founders and raise the bar for the team.

Skills

TypeScript

React/Next.js

Node.js

PostgreSQL

Design system

Ownership mindset

Written communication

AI tools Claude

Small team

Tools

Redis

GraphQL

Fastify

Vercel

DigitalOcean App Platform

Job description

At Experis, a ManpowerGroup company, we specialise in recruiting the best tech talent and matching them with all kinds of organisations, from large corporations to start-ups. We are a company specialising in IT consultancy and the recruitment of professionals in the technology sector across our three practice areas: Business Transformation, Cloud & Infrastructure, and Enterprise Applications. We have a workforce of over 1,800 IT specialists in Spain and an international presence in 54 countries. If you’re a technology professional, we’d love to help you find that new opportunity you’re looking for – the one that will help you take the next step in your career. Find your next opportunity with us. Take your career to the next level with Experis.

About the role

A small, experienced group of engineers, a designer and a founding team that stays close to the product. Engineers own features end to end, work closely with design, and have a direct line to the decisions that matter. We use Claude Team Enterprise as a core part of how we work and expect everyone on the team to do the same. We are a lean team of senior full-stack engineers, and this role sits at the top of that group as the person we rely on when something is hard, ambiguous, or nobody else has the context. This is a hands-on role, roughly 90% coding. We are not looking for a pure architect or someone who wants to direct from a distance. We are looking for someone who is deep in the codebase every day, ships features themselves, and makes pragmatic calls that move the product forward. You will also help shape technical direction, work directly with our founders to turn product ideas into scoped, shippable work, and raise the bar for the whole team.

What you will own

• End-to-end feature delivery across the whole stack: Next.js frontend, Node.js backend, PostgreSQL, and deployment.
• Our real-time analytics dashboard, which gives merchants a single view of ad performance across every channel and platform.
• Our UI component library: long-term ownership of how we build and maintain frontend consistency across the product.
• Infrastructure and reliability: database optimisation, Redis stability, observability, and integrations with ad platforms including Meta, Google, Bing, and Taboola.
• Keeping the product's data layer fast and reliable as we grow: schema and query performance, sensible aggregation, and reporting that holds up under load.

What we are looking for

Must have

• Ability to own a product end to end. We care about demonstrated depth and ownership, not the number.
• Strong TypeScript on both sides: React/Next.js on the frontend and Node.js on the backend.
• Solid PostgreSQL: schema design, query optimisation, and migrations, with the instinct to reason about performance under high write volume.
• Experience maintaining a component library or design system, not just consuming one.
• A genuine end-to-end ownership mentality, from technical design through implementation to deployment, and the pragmatism to ship a good solution rather than chase a perfect one.
• Comfortable making product-facing decisions with limited spec, and translating a rough founder request into something shippable.
• Strong written communication. We are async‑first and clarity matters.
• Comfortable using AI tools such as Claude as part of your daily workflow to increase speed and quality.
• Experience in a small team where you wear multiple hats.

Nice to have

• Ad tech or e-commerce background.
• GraphQL.
• Fastify or similar Node.js frameworks.
• Redis.
• DigitalOcean App Platform or Vercel.

What We Offer

• Full-time remote with flexible hours (CET timezone overlap required)
• Competitive salary
• Claude Team Enterprise access from day one
• Direct influence on technical decisions
• A product used by thousands of real merchants every day