Frontend Engineering Lead

We're looking for a Frontend Engineering Lead to join our Sage HCM Localisation engineering team in Barcelona. This is a hands‑on technical leadership role for a senior frontend engineer who can lead the delivery of complex UI initiatives, guide and mentor engineers, and help modernise a large‑scale enterprise product built across React, Sencha Ext JS, and the Carbon Sage Design System.

This is not a people management role – your leadership is technical and delivery‑focused. You'll provide day‑to‑day direction to UI engineers, own the quality of frontend initiatives end‑to‑end, and be the person the team turns to on hard architectural and implementation decisions. You'll also play a key role in the ongoing migration from Ext JS towards React, ensuring the product evolves sustainably without sacrificing the reliability customers depend on.

This is a hybrid role requiring 3 days per week in our Barcelona office.

• 30 Days:
  Get a thorough understanding of the Sage HCM frontend estate: the Ext JS foundation, the React modules in development, the Carbon Design System implementation, and the current state of technical debt and modernisation priorities. Meet the engineers you'll be leading, as well as QA, solution designers, product owners, and UX collaborators. Begin contributing to active delivery work and technical discussions.
• 60 Days:
  Take technical ownership of one or more UI initiatives end‑to‑end. Lead design and planning sessions, provide implementation direction, conduct code reviews, and support engineers through complex problems. Begin identifying and championing improvements to frontend architecture, testability, and Carbon adoption consistency.
• 90 Days:
  Be the established technical authority for frontend delivery across your product areas. Drive the team's approach to React/Ext JS hybrid architecture, frontend quality standards, and design system alignment. Contribute actively to the modernisation roadmap and be a trusted voice in broader engineering and product discussions.

You'll join the Sage HCM Localisation engineering organisation – a set of cross‑functional delivery teams working across payroll, HR, compliance, integrations, and reporting for an enterprise product with a large, established customer base. The frontend estate reflects the product's maturity:
Ext JS underpins significant core functionality, whilst React is being introduced progressively for new development.

You’ll work closely with backend engineers, QA, solution designers, product owners, and UX teams. The engineering culture values pragmatism, quality, and continuous improvement – and the team has the technical depth to have honest conversations about trade‑offs. There is no line management responsibility attached to this role; your authority comes from your expertise and the quality of your technical direction.

• Technical quality, consistency, and maintainability of frontend delivery across your initiatives
• Adoption of Carbon Design System standards and React best practices across the team
• Progress on technical debt reduction and Ext JS modernisation in your product areas
• Quality of technical direction provided to engineers – evidenced through code reviews, design decisions, and delivery outcomes
• Positive collaboration with QA, product, UX, and backend stakeholders
• Engineers in your team growing in technical confidence and capability

• 5+ years of professional frontend engineering experience, ideally in enterprise, SaaS, or cloud‑based product environments
• Strong hands‑on experience with React, modern JavaScript (ES6+), component‑based architecture, state management, and frontend testing practices
• Solid commercial experience with Sencha Ext JS, including component lifecycle, stores, models, and MVVM/MVC patterns
• Strong knowledge of HTML, CSS, SASS, responsive layouts, browser debugging, accessibility, and performance optimisation
• Demonstrated experience leading technical delivery within Agile teams: estimation, decomposition, dependency management, and risk identification
• Confident working with RESTful APIs, JSON, authentication flows, and complex data‑heavy…