Senior Frontend Engineer (React/TypeScript) - Hybrid Lisbon (2–3 days/week office)

ABOUT THE OPPORTUNITY

Join HumanIT to work with an international fintech building enterprise payment technology. Help shape a growing engineering team in Lisbon and develop products where performance, security and user experience are critical.

This is a full-time opportunity with 2–3 days per week in the office, in central Lisbon near the Portuguese Parliament. Professional proficiency in English, both written and spoken, is required.

We are looking for technically outstanding engineers with deep frontend expertise. Full-stack engineers are welcome if frontend development is their strongest discipline. This role is not suitable for backend-focused engineers with only occasional frontend experience.

PROJECT & CONTEXT

You will develop lightweight JavaScript/TypeScript SDKs and embedded payment components for merchant checkout experiences, alongside sophisticated applications for managing and analysing payments.

The scope includes responsive dashboards, data visualisations and complex configuration workflows. Working with Product, Design and Engineering, you will translate designs into precise, accessible interfaces that perform reliably across browsers and devices.

You will contribute to automated testing, performance optimisation, production debugging, documentation and client-library versioning. Understanding backend services and APIs is valuable, but the role’s primary focus is frontend engineering excellence.

WHAT WE'RE LOOKING FOR (Required)

• Strong evidence of delivering sophisticated, high-performance frontend applications.
• Deep JavaScript and TypeScript expertise, including HTML, CSS, the DOM and browser APIs.
• Strong React experience and understanding of component architecture, application state and data fetching.
• Ability to build responsive, data-intensive interfaces without compromising performance or usability.
• Exceptional attention to visual detail and pixel-accurate implementation.
• Experience developing accessible interfaces aligned with WCAG standards.
• Understanding of browser security, including iframes, CSP, CORS and sensitive-data handling.
• Strong automated testing, debugging and performance optimisation practices.
• Ownership, curiosity and the confidence to question assumptions and explain technical decisions.
• Professional English communication skills.
• Availability to attend the central Lisbon office 2–3 days per week.

NICE TO HAVE (Preferred)

• Next.js experience.
• Experience building framework-agnostic SDKs, hosted fields or embedded checkout components.
• Node.js and Backend-for-Frontend experience, alongside a strong frontend specialisation.
• Experience in payments, fintech or e-commerce.
• Familiarity with PCI DSS and security-sensitive customer journeys.
• Experience using AI-assisted development tools with appropriate review and validation.

Compensation: €2.550 – €3.350/month net, depending on experience and seniority level.

Why HumanIT people stay (4.4 Glassdoor, 89% recommend)

• 15th month salary
• Health insurance covering your family
• Birthday off
• Mobility program for digital nomads
• Real work-life balance

Full benefits:
What it's really like: