Senior Javascript Engineer (React/typescript) - Remote (Madrid)

**Looking for impact in eCommerce?**

Join a market leader in the Shopify ecosystem and help shape the future of online retail.

Vitals is an all-in-one Shopify app that 110+ million shoppers interact with every month across **30,000+ stores worldwide**. We’ve earned a **perfect 5/5 rating** (with thousands of glowing reviews) on the Shopify App Store, placing us in the top 0.1% of 13,000+ Shopify apps.

As a profitable, bootstrapped company, we focus solely on delivering value to our merchants
- no vanity projects or red tape, just a laser focus on building products that drive results. If you’re an experienced JavaScript engineer who thrives on innovation and is excited about using AI-powered development tools to boost productivity, this job is for you.

**Why you should join us**:

- ** Thrive in the Shopify ecosystem**: Be part of a team that’s building one of the most popular apps on Shopify. Your work will directly influence the success of tens of thousands of e-commerce businesses.
- ** Remote-first flexibility**: Work from anywhere (EMEA time zone preferred) with **100% remote** forever.
- **Bootstrapped & stable**: Join a profitable startup with _real_ customers and steady growth. No external investors means we prioritize product quality and user happiness above all else.
- ** Fresh fech & AI-driven culture**: Work with a modern tech stack (TypeScript, Preact/React, Symfony, AWS) and a team that embraces new technologies. We use **AI development tools (like Claude Code and Cursor)** to code smarter and innovate faster.
- ** Direct impact & ownership**: Small, agile team where **transparency, ownership, and diversity** are valued. Your ideas can quickly shape product features used by millions, and you won’t be bogged down by bureaucracy.

**What you will be doing (Responsabilities)**:

- ** Collaborate & ship solutions**: Work closely with product managers and designers to plan, build, and ship new features that **optimize the shopping experience** and drive merchant sales. You’ll be involved end-to-end
- from initial technical analysis and design to coding, review, and deployment.
- ** Leverage AI in development**: Use AI coding assistants (e.g., Claude Code, Cursor) as part of your workflow to accelerate development, ensure code quality, and automate routine tasks. We encourage experimenting with new AI tools to boost productivity.
- ** Front-End development**: Build fast and intuitive UI components and e-commerce features using **TypeScript** and **React/Preact**. Ensure our app’s widgets and interfaces are polished, mobile-friendly, and seamlessly integrated into merchants’ storefronts.
- ** Quality assurance**: Write unit and integration tests (using **Jest, React Testing Library, Playwright**, etc.) to ensure features are reliable and bug-free. You’ll also monitor features in production and quickly squash any issues that pop up.
- ** Mentorship & code reviews**: As a senior engineer, you’ll mentor less-experienced teammates, share knowledge, and lead by example. You’ll participate in code reviews and help uphold high engineering standards across the team.

**What we're looking for (Requirements)**:

- ** Senior Front-End experience**: 8+ years of hands-on JavaScript/FrontEnd development. You have deep knowledge of modern FrontEnd frameworks (preferably React or similar) and TypeScript.
- ** AI-driven developer**: Proven experience or strong interest in using AI tools for development. You’re familiar with tools like **Claude Code, Cursor**, or similar, and you actively use them to improve code quality and delivery speed.
- ** Strong problem solver**: You excel at thinking in trade-offs and choosing the right solution for the situation. There’s no one “right” answer in engineering
- you weigh pros and cons to make pragmatic decisions.
- ** Proactive & product-focused**: You take initiative to identify what needs to be done without always waiting for direction. If something doesn’t feel right (technically or from a user experience perspective), you speak up and propose better solutions.
- ** Resilient & creative**: When faced with an “impossible” task or a complex bug, you get excited by the challenge rather than discouraged. You enjoy brainstorming and aren’t afraid to think outside the box to find a solution.
- ** Strong communicator**: You communicate clearly and early. If a potential issue arises, you raise it before it becomes a blocker. You can explain technical concepts to non-engineers and collaborate well in a remote team.

**Bonus points**:

- ** Polyglot developer**: Experience with multiple FrontEnd frameworks (React, Angular, Vue, etc.), and deep **VanillaJS** expertise. You can quickly adapt to new libraries and paradigms.
- ** Performance tuning**: Knowledge of advanced performance optimization techniques for web apps (lazy loading, caching strategies, minimizing bundle size, etc.). Experience making dynamic storefronts lightning-fast is a plus.
- ** Build tools mastery**: Familiari Postúlate en Kit Empleo: kitempleo.es/empleo/6tzvrp