Senior Frontend Developer (React)

GBL Tech; Portugal; On-site; EUR 55,000 - 85,000; Full time

Job summary

GBL Tech in Portugal is seeking a Senior Frontend Developer (React) to shape the architecture and technical direction of high‑performance web applications. You will lead frontend initiatives, set engineering standards, and build scalable experiences using React and Next.js.

Collaborate with product and cross‑functional teams in an Agile environment, drive performance improvements including Core Web Vitals and SEO, and mentor engineers to maintain high code quality and sustainable delivery.

Qualifications

• Extensive professional experience building high-scale web apps.
• Strong knowledge of TypeScript, React.js, and Next.js.
• Proven Web Performance optimisation including Core Web Vitals, SEO, and accessibility.
• Experience with automated testing (Unit, Integration, E2E) and TDD/Shift-Left.
• Ability to lead architecture decisions and mentor developers.
• Experience in Agile environments.

Responsibilities

• Define and evolve frontend architectures for high-traffic web applications.
• Improve performance via Core Web Vitals, SSR, SSG, ISR, caching, and SEO.
• Establish frontend engineering standards and best practices.
• Define and implement testing strategy across Unit, Integration, and E2E testing.
• Mentor developers and drive engineering decisions.
• Collaborate with product and business stakeholders in Agile environments.

Skills

Typescript

React.js

Next.js

Frontend Architecture

Performance Optimisation

Testing (Unit/Integration/E2E)

TDD

Shift-Left

Agile/Scrum/Kanban

Cross-functional Collaboration

Tools

Azure

AWS

Google Cloud

New Relic

Datadog

Dynatrace

Job description

At GBL Tech, we drive high-impact technology careers through specialization and scale. We operate across critical digital ecosystems — from Fintech to Smart Industry — connecting talent with technically challenging projects and modern stacks.

The Role

We're looking for a Senior Frontend developer (React) to shape the architecture and technical direction of high-performance web applications. This role combines deep frontend engineering expertise with technical leadership, offering the opportunity to influence architectural decisions, establish engineering standards, and build scalable digital experiences using modern React and Next.js technologies.

Your Mission:

• Frontend Architecture: Define and evolve frontend architectures for complex, high-traffic web applications, ensuring scalability, security, maintainability, and long-term technical sustainability.
• Performance Optimisation: Improve application speed and user experience through techniques involving Core Web Vitals, SSR, SSG, ISR, React Server Components (RSC), caching, and SEO.
• Engineering Excellence: Establish and promote best practices across code quality, architecture, accessibility, and frontend development standards.
• Testing Strategy: Define and implement comprehensive testing approaches, covering Unit, Integration, and E2E testing, while promoting TDD and Shift-Left quality practices.
• Technical Leadership: Act as a technical reference for the team, mentoring developers, encouraging knowledge sharing, and driving sound engineering decisions.
• Cross-Functional Collaboration: Work closely with product and business stakeholders to translate requirements into robust technical solutions within Agile, Scrum, and Kanban environments.

What We Are Looking For:

• Frontend Experience: Extensive professional experience in software development, with a strong background in building complex, high-scale web applications.
• React & Next.js Expertise: Advanced knowledge of Typescript, React.js, and Next.js, including architecture and development of sophisticated applications.
• Performance & Accessibility: Proven experience optimising Web Performance, including Core Web Vitals, SEO, and web accessibility.
• Testing & Quality: Strong expertise in automated Unit, Integration, and E2E testing, together with practical experience in TDD and Shift-Left methodologies.
• Technical Leadership: Ability to take ownership of architectural decisions, influence engineering standards, and guide teams towards high-quality, maintainable solutions.
• Cloud & Observability: Familiarity with Azure, AWS, or Google Cloud, as well as monitoring and observability tools such as New Relic, Datadog, or Dynatrace, will be valued.
• Communication & Collaboration: Strong communication skills, autonomy, and a collaborative mindset, with experience working in Agile environments and sharing technical knowledge across teams.