Implementation Engineer

Build AI Products. Own Them for Years. Shape the Future of Engineering in Barcelona.

Full-Time | Permanent

Location: Barcelona, Spain

Open to candidates across the United States & Canada

Relocation to Barcelona, Spain is required

Visa sponsorship and relocation support available

Target Start Date: January 2027 (or as soon as work authorization is completed)

Founded in 1997 , Leyton is a global innovation funding and consulting firm helping organizations innovate, grow, and improve financial performance.

Today, Leyton has 3,000+ professionals across 25+ offices in 17 countries , supporting businesses through innovation, technology, and strategic consulting.

• Research & Development (R&D) Tax Credits
• Energy Efficiency Incentives
• State & Local Tax (SALT)
• Grants & Government Incentives
• Corporate Finance Advisory
• VAT Services
• Property Tax
• Customs Duty Recovery
• Orphan Drug Tax Credits

Across North America and globally, Leyton helps thousands of organizations improve processes, unlock innovation, and create measurable business impact.

At Leyton, innovation goes beyond consulting. We are building the future of enterprise software through Mainloop , our AI-native engineering organization based in Barcelona.

About Mainloop

Mainloop is a new engineering team being built from the ground up in Barcelona, backed by an established international organization with decades of experience, global customers, and a proven technology foundation.

Our mission is simple:

Find complex business processes, understand how they truly work, and build AI-powered software that transforms the way companies operate.

We are building tools that automate professional-services work across approximately 15 countries , eliminating repetitive administrative processes, reducing manual effort, and creating scalable digital products.

This is not a traditional software engineering role.

We are looking for engineers who combine technical ability with consulting instincts — people who want to understand the business problem first, then build the right solution.

The Opportunity

As a Forward Deployed Engineer , you will work directly with business teams across different countries to identify opportunities, design solutions, build prototypes, and deliver AI-powered products.

You will take projects from:

You will work closely with stakeholders, engineers, product owners, and our global technology teams.

What You Will Do

Understand Business Problems

• Travel to different countries and work directly with teams to understand their workflows.
• Learn how processes actually operate, beyond documented procedures.
• Identify inefficiencies, manual work, and opportunities for automation.
• Quantify potential business impact before building solutions.

Design Solutions

• Translate business needs into clear functional requirements.
• Define workflows, users, rules, data movement, and system behavior.
• Create functional architecture documentation that guides development.
• Evaluate existing products and technology before building from scratch.

Build AI-Powered Products

• Use modern AI development tools and coding agents to rapidly prototype and build solutions.
• Create working applications within weeks, not months.
• Build across frontend and backend environments.
• Iterate quickly based on stakeholder feedback.
• Deliver MVPs ready for adoption.

Own Delivery & Handover

• Present prototypes and solutions directly to business users.
• Validate adoption and measure impact.
• Create documentation and handover materials.
• Transition successful products to engineering and product teams.
• Move on to the next business challenge.

What Makes This Role Different

You will not maintain the same product forever.

Your role is to discover, build, validate, and deliver.

Once a solution reaches maturity, ownership moves to our engineering and product teams. You move forward to the next challenge.

You will continuously work on:

• New business processes
• New countries
• New AI-powered solutions

AI-Native Engineering Environment

Mainloop is built around AI from day one.

You will work with:

• AI coding agents
• Automated engineering tools
• Internal technology platforms
• Shared architecture patterns

The expectation is not that you write every line of code manually. <