Our client, a fast-growing international digital marketplace, is building AI-powered products that connect millions of users with trusted service professionals. Operating at large scale, the platform processes high volumes of data and interactions every day, with AI playing a central role in improving matching, trust, automation, and decision-making across the ecosystem.

To support this vision, the company is expanding its senior technical leadership and is looking for an AI Principal Engineer to join its Barcelona-based engineering hub.

In this strategic role, you will sit one level above Senior Engineers, owning a broad end-to-end technical view across systems, architecture, and AI-driven solutions. You will help define where and how AI creates the most value, while guiding teams to turn advanced ideas into reliable, production-grade systems.

Your responsibilities and impact as an AI Principal Engineer:

• Architecting large-scale AI systems, including orchestration frameworks and AI-powered APIs.

• Defining how AI services are integrated across the platform through robust API designs.

• Guiding and mentoring senior engineers working on advanced AI and system design challenges.

• Partnering closely with engineering leadership to translate AI research into scalable systems.

• Setting technical standards and best practices for AI engineering, system design, and performance.

• Providing hands-on technical direction while influencing strategy across the wider engineering organisation.

Skills, qualifications, and interests you need to succeed in this role:

• Deep experience designing and building distributed systems at scale.

• Strong background in API-based architectures and service integrations.

• Hands-on exposure to AI technologies such as LLMs, AI APIs, vector databases, or multi-agent systems.

• Ability to move from prototype to production, balancing experimentation with engineering discipline.

• Strong architectural instincts and a clear understanding of performance and scalability trade-offs.

• Confidence communicating technical direction and mentoring senior engineers.

• Experience in large-scale digital platforms or marketplaces is a plus.

• Fluent English required; Spanish is a plus.

What’s in it for you?

• Competitive salary package aligned with a principal-level role.

• Paid annual leave and Sick leave.

• Maternity, paternity, and partner leave.

• Medical coverage through the national social security system.

• Long-term opportunity in a company where AI is a core strategic pillar.

• High-impact role with strong autonomy and influence on technical direction.

• Barcelona-based position within an international engineering environment.

Your future company

You will join a well-established yet fast-evolving international tech company, trusted by millions of users and professionals. With AI deeply embedded in its platform strategy, the company continues to invest in cutting-edge technology to simplify complex processes, improve trust, and deliver meaningful impact at scale.