Senior/Staff Frontend Engineer

Fonoa

Fonoa

Software Engineering

United Kingdom · London, UK

Posted on May 21, 2026

Location

London, United Kingdom; Zagreb, Croatia

Employment Type

Full time

Location Type

Hybrid

Department

Engineering

About Engineering at Fonoa

Engineering is central to how we build the business. We focus on solving real customer problems, not just shipping features. We work in small, high-trust teams, with full ownership across the lifecycle, from design to production and beyond.

We value:

  • Ownership – engineers own what they build end-to-end

  • Simplicity – we break down complex problems into clear solutions

  • Thinking Big - we innovate with modern technologies (LLMs, AI Agents, etc.) to solve meaningful problems

  • Quality – scalable, maintainable systems are non-negotiable

  • Speed & iteration – we ship fast, learn, and improve continuously

  • Collaboration – we win as a team, not as individuals

Position Overview

As Fonoa continues to evolve beyond APIs into a broader platform experience, we are looking for a Frontend Engineer to help redefine how our products are designed, built, and experienced across the company.

This role goes far beyond implementing interfaces. You will play a foundational role in shaping the future of the Fonoa platform — from customer-facing products and internal tooling to the overall design system, interaction patterns, and frontend architecture that ties everything together.

We are looking for someone who cares deeply about product experience, systems thinking, and frontend craftsmanship. Someone who can work closely with product, engineering, and design to build products that feel fast, intuitive, and thoughtfully designed, while also helping define how frontend engineering operates and scales at Fonoa.

As our platform evolves toward more intelligent, agent-driven workflows, the frontend becomes a critical part of the experience. We want to move beyond traditional dashboards and workflows toward interfaces that feel more dynamic, contextual, and assistant-like, helping customers navigate complex compliance and tax operations in a much more seamless way.

This is a highly collaborative, hands-on role for someone who thrives in ambiguity, enjoys shaping products from first principles, and wants to have a meaningful impact on both the user experience and the engineering culture around frontend development.

We are not looking for someone to simply “build screens.” We are looking for someone who can help define:

  • How products should feel

  • How frontend systems should scale

  • How users interact with increasingly intelligent workflows

  • And how design and engineering work together to create exceptional products

What You Will Be Doing

  • Redesign and evolve product experiences across customer-facing and internal platforms

  • Help define and scale our frontend architecture, patterns, and design systems

  • Build fast, reliable, and intuitive user experiences across web applications

  • Collaborate closely with product, design, and engineering to shape new workflows and features

  • Contribute to the visual identity and frontend standards of the platform

  • Help evolve Fonoa from an API-first company into a broader platform experience

  • Build interfaces that support intelligent, assistant-like, and agent-driven workflows

  • Continuously improve frontend quality, performance, maintainability, and developer experience

  • Mentor and influence frontend standards and practices across the engineering organisation

What We’re Looking For

  • Strong experience building high-quality frontend applications and product experiences

  • Deep understanding of frontend architecture, state management, performance, and scalability

  • Strong product and design instincts, with attention to detail and usability

  • Ability to collaborate closely with designers and product teams from concept to production

  • Experience designing and evolving frontend systems and reusable component libraries

  • Builder mentality with high ownership and strong product thinking

  • Comfortable operating in ambiguity and shaping problems, not just implementing requirements

  • Strong communication and collaboration skills in cross-functional environments

  • Curiosity around AI-driven interfaces and how intelligent workflows change product experiences

API Documentation

For engineers, API design and structure are an important part of evaluating a role. You can explore our API and how we build products here: https://docs.fonoa.com/

Tech Stack

We use these technologies today, but we don’t hire for specific tools. We care about engineers who can understand problems, make good technical decisions, and choose the right tools for the job.

  • Backend: Node.js, Go

  • Frontend: React, TypeScript

  • Infrastructure: GCP, k8s, Terraform, Postgres

Note:
If you don’t think you have the full experience we’re looking for, but you could be a fit and are willing to learn, do apply anyway! We are building a diverse and inclusive team.

As part of the recruitment process at Fonoa, we process your personal data in accordance with our Privacy Notice for Job Applicants. This notice explains how and why your data is collected and used, and how you can contact us if you have any concerns.