Senior AI Systems Engineer - Multi-Agent Systems

Job Description:

Company Description:

We Dream. We Do. We Deliver.

At Merkle, a dentsu company, we power the experience economy. Whether we’re building the next great app, running CRM at scale for global brands, delivering technology architectures that support millions of users, or providing world-class data, identity, and insights solutions, it’s all in the name of crafting experiences that set brands apart from the competition. Backed by dentsu's legacy of innovation and creativity originating in Japan, we’ve spent over 35 years helping brands build loyalty, drive growth, and connect meaningfully with their audiences.

We’ve been named a global “Leader” by top industry analyst firms in categories as wide-ranging as digital transformation and commerce, experience design, engineering and technology integration, digital marketing, data science, CRM and loyalty, and customer data management.

Why choose Merkle?

Innovation at Our Core: As part of dentsu’s global network, Merkle pushes the boundaries of customer experience, integrating creativity, technology, and data to drive real-world impact. For over 35 years, we’ve been innovating to meet the changing needs of our clients.

Global Reach with Local Expertise: With over 16,000 employees across 30+ countries, and part of a 70,000 employees’ network at dentsu, Merkle blends global insights with a deep understanding of local markets to deliver personalized, effective solutions.

Collaborative Culture: At Merkle, your ideas and contributions truly matter. You’ll join a team that fosters innovation, collaboration, and creative problem-solving. Together, we work on impactful international projects, making meaningful connections every step of the way.

Role Description:

About the Role

We're looking for a full-stack engineer to build and deploy multi-agent AI systems at enterprise scale. You'll design autonomous agent networks that solve real operational challenges, working across cloud infrastructure, backend services, and AI frameworks—using Claude and modern AI tools to accelerate development.

What You'll Do

• Build Multi-Agent Systems: Design and implement agent architectures using LangChain and LangSmith to orchestrate specialized agents for complex workflows.
• Full-Stack Development: Build production backends in Node.js and craft frontends for human-agent interaction; leverage AI (Claude, Cursor) to ship faster.
• AWS Infrastructure: Deploy and scale agent services on AWS (EC2, Lambda, managed services) with hands-on deployment experience.
• Observability & Reliability: Monitor agent behavior, token efficiency, and latency using LangSmith; implement fallback logic and state management for high task completion.
• Client Collaboration: Work with clients to define agent use cases, refine architectures, and iterate on deployed systems.

What We're Looking For

• Node.js & Full-Stack: Strong backend development in Node.js/TypeScript; comfortable building or working with frontends (React/Next.js).
• AWS Fluency: Practical, hands-on experience deploying and managing production workloads on AWS.
• AI-Powered Development: Daily user of Claude, Cursor, or similar AI coding tools; comfortable building with LangChain and LangSmith.
• Agent Architecture: Experience building or working with multi-agent systems (LangGraph, AutoGen, CrewAI, or custom implementations).
• Shipping Mentality: Ability to move quickly from concept to production; strong communication with technical and non-technical stakeholders.

Nice to Have

• Experience with agent evaluation, self-correction loops, or memory architectures.
• Background in consulting or product studios shipping AI-driven features.
• Python capability for specialized AI services.

*Work visa sponsorship is not available. For local documentation (NIF, NISS), please consult Portuguese authorities.

Additional Information:

Benefits and perks:

🌴25 vacation days

🤝 Enjoy 2 additional volunteering days to support your passion project

💖 Mental Health: Benefit from 3 extra wellness days on top of your vacation days and a Mental Health First Aider and Employee Assisstance program to support your well-being

🏥 Health insurance (also possible for family members)

💻 Cutting Edge Technology & Latest IT tools

🏢 Software-house environment

⌛ Agile and Flexible working hours

🌍 Hybrid working: we combine flexibility with in-person collaboration, with an expectation of 1 day per week/ 4 days per month in the office

✈️ Digital nomad policy

🚀 Focus on career development

🎓 Full access to Dentsu Academy, our global online learning platform

🍻 Beers, foosball, and ping-pong! #workhardplayhard

🥐 Free breakfast every second Wednesday of the month

🛍️ Employee discounts

🎉 Team & Company events

💸 Referral bonus program

*At dentsu, Diversity, Equity, and Inclusion (DEI) is central to our vision: "To be at the forefront of people-centered transformations that shape society."

We cherish the unique talents and perspectives of all individuals, welcoming applicants regardless of gender, gender identity, nationality, religion, ethnicity, cultural background, sexual orientation, age, physical or mental ability. By embracing diverse perspectives, we create meaningful change and sustainable growth for our people, clients, and society. Our hiring decisions are guided by qualifications and role-specific requirements, ensuring a workplace free from discrimination and harassment.

#LI-Hybrid #LI-MERKLE

Location:

Lisbon

Brand:

Merkle

Time Type:

Full time

Contract Type:

Permanent