Senior Fullstack engineer – Frontend & UI Components (All Genders)

📍 Job Overview

Job Title: Senior Fullstack Engineer – Frontend & UI Components Company: zooplus SE Location: Madrid, Spain Job Type: Full-time Category: Software Engineering / Frontend Platform Date Posted: 2026-02-20 Experience Level: 5-10 Years Remote Status: Hybrid

🚀 Role Summary

• Design, build, and evolve core frontend architecture, including Next.js application shell, routing, and rendering engines to empower product teams.
• Enhance the developer experience within a large-scale mono-repository, focusing on workflow improvements, automation, and code quality for hundreds of workspaces.
• Drive the evolution of a block-based rendering architecture, enabling runtime composition and fine-grained observability for customer-facing pages.
• Collaborate closely with architects, designers, and product teams to refine the design system, scalability strategy, and governance model for shared UI components.
• Mentor and coach fellow engineers on best practices in performance, testing, and code quality, acting as a champion for standardization and efficient delivery.

📝 Enhancement Note: This role is positioned within a "Frontend Platform Team," indicating a focus on building foundational systems and tooling that other product teams consume. The responsibilities heavily lean towards enabling other engineering teams through robust architecture, efficient workflows, and high-quality shared components, rather than direct feature development for end-users. The "Platform mindset" is a critical aspect to highlight.

📈 Primary Responsibilities

• Design, build, and continuously evolve the application core, including the Next.js shell, routing mechanisms, and the block-based rendering engine, ensuring robust and scalable solutions.
• Develop and maintain shared Software Development Kits (SDKs) that are critical for all frontend teams across the organization, ensuring consistency and ease of use.
• Drive improvements within the mono-repository workflow by implementing guidelines, conducting thorough reviews of cross-package pull requests, automating release processes, and championing overall code quality.
• Partner closely with architects and designers to refine the block-based architecture, enhance the design system, define the scalability strategy, and establish a clear governance model for shared assets.
• Coach and mentor product-team engineers on best practices related to performance optimization, comprehensive testing strategies, and maintaining high code quality, while actively unblocking delivery and advocating for standardization.
• Lead automation initiatives by identifying key bottlenecks in the development and deployment lifecycle and implementing effective automated solutions to streamline processes.
• Contribute across the entire delivery lifecycle, from initial discovery and proof-of-concept development to coding, code reviews, infrastructure management, and post-mortem analysis for continuous improvement.

📝 Enhancement Note: The responsibilities emphasize a "platform-as-a-service" approach for internal development teams. Key areas include architectural ownership, cross-team enablement, and process optimization within a complex mono-repo environment. The emphasis on "coaching" and "mentoring" suggests a strong senior-level expectation for knowledge sharing and technical leadership.

🎓 Skills & Qualifications

Education: While no specific degree is mandated, a strong foundation in Computer Science principles is implied through the required experience and technical depth. Experience: 5+ years of professional software development experience, with a focus on modern frontend technologies and full-stack capabilities.

Required Skills:

• Professional development experience with TypeScript, React, and Node.js (or similar JavaScript/TypeScript ecosystems) for over 5 years.
• Deep understanding and practical application of modern Continuous Integration/Continuous Deployment (CI/CD) pipelines, including test automation strategies.
• Proven experience with cloud-native deployments, including hands-on work with Docker, Kubernetes, and cloud platforms such as AWS.
• Strong architectural skills, encompassing modular design principles, scalability considerations, performance optimization techniques, and API contract definition.
• Hands-on experience with production systems, demonstrating a history of working effectively within distributed systems environments.
• Demonstrated ability to engage in cross-team discussions, implement technical standards, and effectively mentor junior engineers.
• Excellent verbal and written communication skills in English for effective collaboration in a multinational team.

Preferred Skills:

• Experience in building developer-platform products or internal frameworks, showcasing an understanding of internal customer needs.
• Proven experience maintaining large-scale mono-repositories using tools like Nx, Bazel, Turborepo, or similar, alongside experience with design system libraries.
• Knowledge of experimentation and personalization tooling (e.g., Optimizely, audience targeting platforms).
• Familiarity with key e-commerce performance Key Performance Indicators (KPIs) such as Largest Contentful Paint (LCP), bounce rate, and conversion rates.
• Exposure to server components, edge rendering, and advanced caching strategies within web application development.
• Experience with Infrastructure as Code (IaC) tools like Terraform or AWS CDK, and a strong understanding of AWS services.
• Active participation in open-source or inner-source communities, demonstrating a passion for collaborative development.

📝 Enhancement Note: The "Must-have" qualifications clearly define a senior-level engineer with broad experience across frontend, backend (Node.js), cloud infrastructure, and architectural design. The "Nice-to-have" skills point towards candidates who have specifically worked in platform engineering, large-scale mono-repos, or e-commerce environments, offering a significant advantage.

📊 Process & Systems Portfolio Requirements

Portfolio Essentials:

• Demonstrations of designing and building foundational application components, such as core shells, routing systems, or rendering engines, highlighting architectural decisions and impact.
• Case studies showcasing contributions to mono-repository workflows, including examples of implemented guidelines, automated releases, or significant code quality improvements.
• Examples of collaborative work with architects and designers, illustrating contributions to design systems, scalability strategies, or governance models.
• Evidence of coaching or mentoring other engineers, with examples of how best practices were advocated for and adopted, leading to improved performance or quality.
• Projects demonstrating leadership in automation efforts, identifying bottlenecks, and implementing solutions that increased efficiency or reduced manual effort.

Process Documentation:

• Documentation of architectural designs for complex systems, including trade-offs considered, scalability plans, and performance considerations.
• Workflow diagrams or process descriptions illustrating contributions to mono-repo management, release automation, or cross-package dependency management.
• Examples of technical documentation or design docs that facilitated cross-team understanding and adoption of new architectural patterns or shared components.
• Post-mortem analyses or project retrospectives that demonstrate a commitment to learning from incidents and continuously improving processes and systems.

📝 Enhancement Note: For a Senior Fullstack Engineer in a platform role, a portfolio should emphasize architectural leadership, internal tooling, and process optimization. Candidates should be prepared to showcase how they've enabled other teams, improved development velocity, and contributed to the overall health and scalability of the engineering ecosystem.

💵 Compensation & Benefits

Salary Range: Based on market research for Senior Fullstack Engineers with 5-10 years of experience in Madrid, Spain, and considering the hybrid work model and benefits offered, a competitive annual salary range would typically fall between €55,000 - €75,000 gross per year. This range can fluctuate based on the candidate's specific experience, interview performance, and the exact scope of responsibilities.

Benefits:

• 28 Annual Vacation Days: Generous paid time off to ensure work-life balance.
• Private Medical Health Insurance: Comprehensive health coverage for employees.
• Hybrid Working Model: Flexibility to work from home up to 40% of the month, balancing office collaboration with remote work.
• Development Opportunities: Access to programs and resources to shape individual career paths.
• Training and Support: Opportunities for continuous learning and skill enhancement.
• Wellbeing Offers: Programs designed to support employee health and overall well-being.
• Subsidised Transport: Financial assistance for commuting.
• Bike Leasing: Option to lease bicycles, promoting sustainable and healthy commuting.
• Product Discount: A significant discount on zooplus products, reflecting the company's core business.
• International Work Option: Opportunity to work remotely from approved countries for up to 20 days per year.

Working Hours: The role is based on a standard 40-hour work week, with a hybrid model allowing for up to 40% remote work (approximately 3 days per week in the office).

📝 Enhancement Note: The salary range is an estimate based on industry benchmarks for senior engineering roles in Madrid. The benefits package is comprehensive, emphasizing work-life balance, professional development, and employee well-being, which are attractive to experienced engineers.

🎯 Team & Company Context

🏢 Company Culture

Industry: E-commerce (Pet Supplies) Company Size: zooplus SE is a significant player in the European pet e-commerce market. While the exact number of employees in the Madrid office isn't specified, the company operates across multiple European countries (Munich, Madrid, Krakow, Wroclaw, London, Vienna), suggesting a large, international organization likely employing several thousand people globally. This scale implies robust processes and a structured approach to engineering. Founded: Over 25 years ago, indicating a mature company with a long-standing presence and established market position in the pet e-commerce sector.

Team Structure:

• The "Frontend Platform Team" is a specialized unit within the broader Product & Tech department.
• This team operates with a "platform mindset," treating other product teams as its primary customers.
• The team is distributed across Europe, comprising individuals with diverse nationalities and a collective wealth of experience within zooplus.
• Collaboration is emphasized through pair programming, design documentation, and regular cross-team work.

Methodology:

• Platform-as-a-Service: The team's core mission is to provide foundational architecture, mono-repository management, SDKs, and developer experience tooling.
• Scalability: Focus on scaling the mono-repo to support hundreds of workspaces and ensuring the block-based architecture can handle high traffic and complex rendering.
• Collaboration: Emphasis on English as the primary language for communication, design docs, pair programming, and cross-team initiatives.
• Data-Driven Improvement: While not explicitly detailed for this team, the company's success in e-commerce implies a data-driven approach to product development and operational efficiency.

Company Website: https://www.zooplus.com/ (The provided URL was for jobs, this is the main company site for context)

📝 Enhancement Note: Zooplus's long history and focus on e-commerce suggest a culture that values innovation, customer satisfaction (both end-users and internal development teams), and adaptability in a competitive market. The "power of plus" slogan hints at a culture of continuous improvement and adding value.

📈 Career & Growth Analysis

Operations Career Level: This role is a "Senior Fullstack Engineer," placing it at an experienced individual contributor level. It signifies a move beyond junior or mid-level development, requiring architectural foresight, technical leadership, and the ability to mentor others. The emphasis on platform ownership means this role contributes to the company's engineering foundation and developer productivity.

Reporting Structure: The role is within the "Frontend Platform Team," which is part of the "Product & Tech" department. The engineer will likely report to a Team Lead or Engineering Manager responsible for the platform initiatives. Collaboration will be extensive with architects, designers, and engineers from various product teams.

Operations Impact: The impact is significant and indirect. By providing a robust, scalable, and efficient frontend platform and developer experience, this role enables numerous product teams to ship features faster, safer, and with greater consistency. This directly influences the customer experience, conversion rates, and overall business velocity for zooplus across Europe. The "high impact – high visibility" project aspect underscores this.

Growth Opportunities:

• Technical Specialization: Deepen expertise in areas like Next.js, mono-repo architecture, design systems, and performance optimization, potentially becoming a recognized expert in these domains.
• Leadership & Mentorship: Progress into a Tech Lead role within the platform team or a similar specialized group, taking on more responsibility for technical direction and team guidance.
• Architectural Design: Transition into a more formal Architect role, focusing on long-term technical strategy and cross-team technical alignment.
• Cross-functional Exposure: Gain broader understanding of e-commerce operations, product strategy, and other engineering disciplines through extensive collaboration.
• International Mobility: Leverage the company's multinational presence for potential future opportunities in other offices.

📝 Enhancement Note: This role is ideal for experienced engineers who enjoy building foundational systems, improving developer workflows, and have a passion for enabling other teams. The growth path is geared towards technical leadership and deep specialization within platform engineering.

🌐 Work Environment

Office Type: The company offers a hybrid working model, with employees expected to spend approximately 60% of their time in the office and 40% at home. This suggests a modern office environment designed to foster collaboration and team interaction. Office Location(s): The specific office is located at Génova 17, 5plta, Madrid, Spain. This central Madrid location likely offers good accessibility for local employees.

Workspace Context:

• Collaborative Environment: The hybrid model and emphasis on pair programming, design docs, and cross-team work indicate a culture that values in-person collaboration for brainstorming, problem-solving, and knowledge sharing.
• Operations Tools & Technology: The team utilizes a sophisticated tech stack including React, Next.js, TypeScript, Node.js, pnpm, Turborepo, Jest, Playwright, Docker, Kubernetes, AWS, and Terraform. This implies access to modern development tools and infrastructure.
• Operations Team Interaction: Opportunities for regular interaction with the distributed Frontend Platform Team, as well as extensive collaboration with engineers and architects from various product teams within zooplus.

Work Schedule: The standard working hours are 40 per week. The hybrid model provides flexibility, allowing employees to structure their workdays to balance in-office collaboration with focused, remote work sessions. The option to work from approved countries for up to 20 days annually adds an element of international flexibility.

📝 Enhancement Note: The hybrid model is a significant aspect of the work environment, requiring self-discipline and effective communication skills. The Madrid office is a hub for this international team, providing a base for essential in-person collaboration.

📄 Application & Portfolio Review Process

Interview Process:

• Initial Screening: A brief call with a recruiter to assess basic qualifications, cultural fit, and interest in the role.
• Technical Interview(s): Likely involves one or more in-depth technical discussions, potentially including live coding exercises, system design problems, and deep dives into past projects. Expect questions on TypeScript, React, Node.js, architecture, and performance.
• System Design / Architecture Discussion: A session focused on designing scalable systems, discussing architectural patterns, trade-offs, and how to build robust platforms. This is where portfolio examples related to architecture will be critical.
• Team/Culture Fit Interview: A conversation with team members or a hiring manager to assess collaboration style, communication skills, and alignment with zooplus's values and the team's "platform mindset."
• Final Interview: Potentially with a senior leader or department head to discuss overall fit, career aspirations, and finalize the offer.

Portfolio Review Tips:

• Focus on Impact & Scale: For this role, prioritize projects demonstrating impact on other teams, scalability of solutions, and efficiency gains achieved.
• Architectural Decision Rationale: Clearly articulate the "why" behind your architectural choices. Use case studies to explain the problem, your proposed solution, the technologies used, the trade-offs considered, and the measurable outcomes.
• Mono-repo & Developer Experience: If you have experience with mono-repos or improving developer workflows, highlight specific examples of how you streamlined processes, automated tasks, or enhanced tooling.
• Code Quality & Mentorship: Showcase examples where you championed code quality, implemented robust testing strategies, or mentored junior developers.
• Concise & Visual: Use diagrams, flowcharts, and concise summaries to present complex technical information effectively. Be prepared to walk through your portfolio items verbally.

Challenge Preparation:

• System Design: Be ready to design a scalable frontend platform, a complex rendering engine, or a robust mono-repo tooling solution. Focus on modularity, performance, maintainability, and developer experience.
• Coding Challenges: Expect problems related to JavaScript/TypeScript, React component design, Node.js API development, or performance optimization.
• Scenario-Based Questions: Prepare for questions like "How would you onboard a new team to our mono-repo?" or "How would you improve the performance of a large-scale Next.js application?"

📝 Enhancement Note: The interview process will heavily scrutinize architectural skills, experience with large-scale systems, and the ability to operate within a platform-centric team. A portfolio that clearly demonstrates these capabilities will be crucial.

🛠 Tools & Technology Stack

Primary Tools:

• Core Stack: React, Next.js (including server & client components), TypeScript, Node.js, PostgreSQL.
• Mono-repo Tooling: pnpm workspaces, Turborepo, Changesets (for versioning and publishing).
• Testing: Jest (unit/integration testing), Playwright (end-to-end testing).
• CI/CD: Jenkins pipelines, Docker, Kubernetes.
• Observability: Prometheus/Grafana (metrics), Sentry (error tracking), Elasticsearch/Kibana (log analysis).
• Cloud: AWS (S3, CloudFront, Lambda@Edge, RDS), Terraform (Infrastructure as Code).

Analytics & Reporting:

• Metrics: Prometheus/Grafana for real-time monitoring and performance tracking.
• Error Tracking: Sentry for identifying and diagnosing application errors.
• Log Analysis: Elasticsearch/Kibana for deep insights into application behavior and debugging.

CRM & Automation:

• While not explicitly listed for this role, the company likely utilizes CRM and marketing automation tools for its core e-commerce business. The focus here is on the engineering stack, not business operations tools.

📝 Enhancement Note: Proficiency across this broad stack is essential. Candidates should be comfortable with modern JavaScript frameworks, build tools, containerization, cloud infrastructure, and observability tools. Experience with Next.js server/client components and edge rendering is particularly valuable.

👥 Team Culture & Values

Operations Values:

• Platform Mindset: Treating internal product teams as customers, prioritizing their velocity, satisfaction, and ease of use for the platform components and tooling.
• Collaboration & Transparency: Working closely with diverse, multinational teams, utilizing pair programming, design docs, and open communication in English to foster a shared understanding and collective ownership.
• Continuous Improvement & Innovation: Embracing change, adapting to challenges, and constantly seeking ways to do better, whether through architectural evolution, workflow optimization, or new technology adoption.
• High Impact & Ownership: Taking pride in working on high-impact, high-visibility projects that directly contribute to the success of millions of customers and the company's growth.
• Quality & Reliability: Championing code quality, robust testing, and scalable architecture to ensure dependable performance for customer-facing applications.

Collaboration Style:

• Distributed & English-Speaking: The team is geographically distributed across Europe, with English as the primary language of communication.
• Cross-Functional Integration: Close collaboration with product teams, architects, and designers is a core aspect of the role, requiring strong interpersonal and communication skills.
• Process-Oriented: Emphasis on structured processes like design documentation, code reviews, and pair programming to ensure alignment and knowledge sharing.
• Mentorship & Knowledge Sharing: A culture of coaching and mentoring engineers to elevate the collective technical skill and adherence to best practices.

📝 Enhancement Note: The "platform mindset" is the most distinctive cultural element. Candidates need to demonstrate an understanding of how to serve internal customers and prioritize the needs of other development teams when building foundational engineering solutions.

⚡ Challenges & Growth Opportunities

Challenges:

• Scaling a Mono-repo: Managing and scaling a large mono-repository to hundreds of workspaces presents significant technical and organizational challenges related to build times, dependency management, and code conflicts.
• Complex Architecture: Evolving a block-based rendering engine and shared SDKs requires deep technical understanding, careful planning, and meticulous execution to avoid introducing regressions.
• Balancing Standardization and Autonomy: Coaching product teams requires finding the right balance between enforcing platform standards for consistency and allowing teams the autonomy to innovate and deliver features quickly.
• Distributed Team Collaboration: Effectively collaborating and maintaining alignment across a geographically distributed team requires strong communication skills and proactive engagement.
• High Impact, High Visibility: Working on core systems means that any issues can have a widespread impact, requiring a high degree of diligence and responsibility.

Learning & Development Opportunities:

• Advanced Next.js & React: Deep dive into server components, client components, edge rendering, and advanced caching strategies within the Next.js ecosystem.
• Mono-repo Tooling Mastery: Become an expert in tools like Turborepo, pnpm, and Changesets for managing large-scale monorepos.
• Developer Productivity & DX: Learn and implement best practices for developer experience, automation, and internal tooling to significantly boost engineering efficiency.
• Scalability & Performance Architecture: Gain extensive experience in designing and scaling complex web applications and platform components.
• Mentorship & Technical Leadership: Develop leadership skills through coaching, technical guidance, and contributing to architectural strategy.

📝 Enhancement Note: This role offers a prime opportunity to tackle complex, large-scale engineering challenges at the heart of a major e-commerce platform, with significant potential for professional growth in specialized areas of frontend platform development.

💡 Interview Preparation

Strategy Questions:

• "Describe a time you designed and built a core component or SDK for a platform team. What were the key architectural decisions, and what was the impact?"
  • Preparation: Focus on a project where you built something foundational. Detail the problem, your solution (architecture, technologies), the trade-offs you made, and quantifiable results (e.g., improved developer velocity, reduced errors, increased adoption).
• "How would you approach improving the developer experience within a large-scale mono-repository like ours? What specific strategies or tools would you consider?"
  • Preparation: Think about common mono-repo pain points (slow builds, complex dependencies, release management). Discuss strategies like optimizing build tools (Turborepo), improving CI/CD, standardizing workflows, and enhancing local development setups.
• "Imagine a product team is struggling to integrate with our shared design system or SDKs. How would you diagnose the issue and help them succeed while maintaining platform standards?"
  • Preparation: Emphasize a collaborative and empathetic approach. Discuss active listening, debugging techniques, providing clear documentation or examples, and potentially refining the platform offering based on feedback.

Company & Culture Questions:

• "What does a 'platform mindset' mean to you, and how have you applied it in previous roles?"
  • Preparation: Connect this to internal customer focus, enabling other teams, and prioritizing shared infrastructure and tools over individual feature development.
• "How do you approach mentoring engineers and coaching them on best practices, especially in a distributed team environment?"
  • Preparation: Discuss your communication style, methods for providing constructive feedback, creating learning resources, and fostering a culture of knowledge sharing.
• "Given our focus on e-commerce, what are some key performance metrics you'd consider critical for a frontend platform, and how would you measure their impact?"
  • Preparation: Think beyond just LCP. Consider developer productivity metrics (e.g., PR cycle time, deployment frequency), adoption rates of platform components, and how platform performance indirectly impacts business KPIs (conversion, bounce rate).

Portfolio Presentation Strategy:

• Structure: Organize your portfolio by key areas: Architecture, Developer Experience/Mono-repo, Collaboration/Mentorship.
• Storytelling: For each project, use the STAR method (Situation, Task, Action, Result) or a similar framework. Clearly articulate the problem, your role, the actions you took, and the measurable outcomes.
• Visuals: Use diagrams (architecture, flowcharts), screenshots, and code snippets (where appropriate) to illustrate your points.
• Focus on Impact: Quantify your achievements whenever possible. Highlight how your work benefited the team, the product, or the company.
• Conciseness: Be prepared to present your key projects within a limited timeframe, focusing on the most relevant aspects for this role.

📝 Enhancement Note: The interview process will likely involve a mix of technical depth, architectural thinking, and an understanding of how to build and maintain internal developer platforms. Candidates should be ready to articulate their experience with complex systems and their ability to lead and mentor.

📌 Application Steps

To apply for this Senior Fullstack Engineer position:

• Submit your application through the provided SmartRecruiters link.
• Customize Your Resume: Tailor your resume to highlight your experience with TypeScript, React, Node.js, Next.js, mono-repo management, and CI/CD. Use keywords from the job description, such as "platform mindset," "developer experience," "scalability," and "architecture."
• Prepare Your Portfolio: Select 2-3 of your most impactful projects that demonstrate your architectural skills, experience with large-scale systems, and contributions to developer productivity or platform development. Be ready to articulate the "why," "how," and "what" of these projects.
• Practice System Design: Review common system design patterns for scalable web applications and developer platforms. Be prepared to discuss trade-offs and justify your design choices.
• Research zooplus: Understand their business model, their position in the e-commerce market, and their commitment to their "power of plus" culture. This will help you tailor your answers and demonstrate genuine interest.

⚠️ Important Notice: This enhanced job description includes AI-generated insights and operations industry-standard assumptions. All details should be verified directly with the hiring organization before making application decisions.