Full Stack Developer

We’re looking for a hands-on Full-Stack Developer to build and scale the internal tools and AI-powered applications that support Merkle’s delivery. You’ll own the application layer end-to-end - from the backend up through the frontend - covering backend logic, infrastructure, authentication, deployments, and day-to-day stability.

What You’ll Do

• Own and maintain the full application stack across our internal tools: backend, database, auth, and frontend
• Design and implement authentication and access control (e.g., SSO with SAML or Okta, multi-tenant data isolation, role-based access)
• Write and maintain database schemas, migrations, and access policies (e.g., PostgreSQL with RLS and RPC functions)
• Build and manage serverless backend functions (e.g., for application logic and API integrations)
• Set up and maintain CI/CD pipelines and manage deployments across environments (e.g., DEV, UAT, PROD)
• Build and maintain modern frontends (e.g., React, Vite, TypeScript)
• Debug and resolve issues across the stack (e.g., build errors, networking, misconfigured services, 5xx errors)
• Collaborate with the AI/LLM side of the team to integrate model outputs cleanly into the application
• Take ownership from idea → build → run → improve

What You Bring

• 3+ years in software engineering (full-stack, AI, or platform development)
• Experience with modern JavaScript/TypeScript stacks (React, Next.js, Node.js), frontend and backend
• Experience with Docker and self-hosted infrastructure, not just managed cloud services
• Knowledge and experience with multi-tenant application patterns
• Solid problem-solving skills and strong ownership mindset

Strong advantage:

• Familiarity with backend-as-a-service platforms (e.g., Supabase, Firebase) for auth, database, storage, and serverless functions
• Exposure to alternative JS/TS runtimes (e.g., Deno, Bun)

Nice to Have

• Hands-on experience with LLM APIs (e.g., OpenAI, Anthropic)
• Familiarity with SSE streaming or real-time data patterns
• Familiarity with MarTech platforms (e.g., Adobe, Salesforce, CDPs)
• Experience with authentication systems (e.g., OAuth2, SAML, SSO)

Why This Role

• Build products, not projects
• Direct impact on how Merkle delivers at scale
• Work at the intersection of AI, engineering, and platform thinking
• High ownership and room to shape solutions

What We Offer

• A dynamic, international work environment with colleagues from around the globe.
• A challenging position at a successful company in a growing market.
• A fun and inclusive culture-think foosball, table tennis, themed events, and team parties.
• 3 extra days off (yes, at Merkle we take your well-being very seriously) - in addition to 25 annual vacation days, there are 3 Well-being Days.
• 2 Social Impact Days - you can volunteer for a charity of your choice.
• Extensive learning and development opportunities, including a wide range of personal and online training.
• A hybrid work model, with 2-3 days in the office and the rest working from home.
• A competitive salary and excellent secondary benefits.

Company Description Merkle, a dentsu company, powers the experience economy. For over 35 years, Merkle has placed people at the heart of its digital business transformation approach. As the only integrated experience consultancy with a heritage in data science and business performance, Merkle delivers holistic, end-to-end experiences that drive growth, engagement, and loyalty. Recognized as a "Leader" by top industry analysts in categories such as digital transformation, commerce, experience design, engineering, technology integration, digital marketing, data science, CRM, loyalty, and customer data management, Merkle operates in 30+ countries with over 16,000 employees. In the Netherlands, more than 150 Merkle employees work with clients like ASML, Albert Heijn, HEMA, Carglass, and Signify. Merkle Netherlands is a strategic partner of Google, Adobe, Salesforce, and Selligent. For more information, visit www.merkle.com.

Diversity and Inclusion At dentsu we believe in the power of diversity. We welcome all applications regardless of age, disability, gender reassignment, marital or civil partner status, pregnancy or maternity, race, color, nationality, ethnic or national origin, religion or belief, sex, or sexual orientation.

Contact: We look forward to receiving your application for any questions, please contact the TA in charge of this role: David Ryall, Senior Talent Acquisition Partner, EMEA, NE.

Location: Rotterdam

Brand: Merkle

Time Type: Full time

Contract Type: Fixed Term Contract (Fixed Term)