Senior Frontend Engineer

Ifx-Payments; City Of London; On-site; GBP 90,000 - 120,000; Full time

Job summary

Ifx-Payments in London is seeking a Senior Frontend Engineer to join the Technology team. You will own the design and implementation of a React-based SPA that orchestrates complex forms and onboarding flows for clients and sub-accounts.

We expect strong React/TypeScript experience, deep form engineering, and a pragmatic approach to AI tooling with a focus on customer outcomes. This full-time role sits in a fast-growing fintech”, with security and observability baked in.

Qualifications

• Strong track record building modern SPAs in React and TypeScript with production use.
• Complex form engineering including onboarding cohorts and cross-field dependencies.
• Multi-step flow state and persistence across reloads.
• Server-state architecture using TanStack Query and route loaders.
• Third-party integrations with identity verification and OpenAPI clients.
• Roles and permissions enforced in UI and API.
• Testing as a habit with Vitest, RTL, MSW and coverage gate.
• WCAG 2.1 AA accessibility in Tailwind/Radix/shadcn.

Responsibilities

• Design and build new features in a form-heavy React SPA.
• Thoroughly test everything to prove reliability.
• Make architectural calls for your domain and defend them in tribe reviews.
• Build in security, reliability and observability from day one.
• Leverage AI tooling sensibly and responsibly.
• Review code and mentor less experienced engineers.

Skills

React

TypeScript

Form engineering

State management

Testing with Vitest

Accessibility WCAG

Communication

Tools

TanStack Query

Radix/shadcn

Vitest

RTL

MSW

Storybook

Vite

Azure Static Web Apps

Azure DevOps

Job description

Senior Frontend Engineer

Department: Technology

Employment Type: Permanent - Full Time

Location: London

Reporting To: Matt Millross

Description

Overview of the role

• This role sits in the Accounts tribe, which owns the onboarding of clients and their accounts, including KYC/KYB across corporate, fund, intermediaries and sub-accounts.
• You will be part of a team building a single page application that runs on React 18, TypeScript (strict), TanStack Query / Form / Router, Tailwind + a Radix/shadcn component system, Vitest + RTL + MSW.
• You make the design calls on your domain and argue them out with the tribe. You build it, you run it, you own it. We are after someone who owns customer outcomes, takes responsibility to ensure their software works and sounds the alarm if we are attempting to build the wrong things.

Key Responsibilities

• Design and build new features in a form-heavy, React single page application
• Thoroughly test everything you build to prove your software works
• Make architectural calls on your domain, record down, present and defend them in front of the tribe.
• Build in security, reliability and observability from the start.
• Use AI tooling well. We use Claude Code daily and we expect judgement about where it earns its place and where it doesn't.
• Review code, raise the standard around you, and help less experienced engineers get better.

Skills, Knowledge and Expertise

• A strong track record of building modern single-page applications in React and TypeScript, running in production with real users.
• Complex form engineering. Four onboarding cohorts, branching validation and cross-field dependencies.
• Multi-step flow state. Long journeys that a client leaves and returns to. You must reason about where the state lives and what happens on a reload.
• Server-state architecture. TanStack Query at depth: query-key design, cache invalidation, stale policies and prefetch through route loaders.
• Third-party integration. Identity verification, document upload and OpenAPI-generated API clients.
• Roles and permissions. Enforced in the interface as well as the API.
• Testing as a habit. Vitest, React Testing Library and MSW, against a coverage gate that fails the build. You can say what a piece of code is actually protected against.
• Accessibility to WCAG 2.1 AA, in Tailwind with a Radix/shadcn component system and a Storybook library.
• Real experience building software with AI, not just an interest in it. We want someone with a feel for when it helps and when it is quietly making a mess.
• Clear communication with engineers and non-engineers, including the willingness to disagree, and to commit once the call is made.

Useful, but not required

• Auth0, or a similar identity provider.
• Sentry, or similar error tracking and observability.
• Azure Static Web Apps and Azure DevOps, or comparable CI/CD.
• Vite build and bundle work — chunk splitting, bundle analysis, source maps.
• A background in regulated financial services, KYC/KYB or client onboarding.
• Storybook, or another documented component library.
• Real-time updates over WebSockets or SignalR.
• If you've done any of it, say so. If you haven't, we'd rather teach you that than compromise on the engineering.

Our Development Environment

• React 18, TypeScript in strict mode and Vite, deployed to Azure Static Web Apps. The business logic sits behind APIs, so the front end owns orchestration, state and complex forms.
• Azure DevOps for planning and CI/CD.
• Grafana and Application Insights for observability.
• Claude Code in daily use.
• Autonomous teams, short paths between a decision and it being live
• A macbook pro for your workstation

Benefits

We believe great people do their best work when they feel supported, rewarded, and empowered to grow. That’s why we offer a benefits package designed to support your career, wellbeing, finances, and life outside of work.

• • 25 days’ annual leave, plus bank holidays
  • An extra day off for your birthday
  • Holiday loyalty scheme rewarding long-term service
  • Work abroad scheme for added flexibility
• • Competitive pension scheme via salary exchange
  • Annual discretionary bonus scheme (eligible after probation)
  • Financial education, planning & coaching platform
  • Interest‑free Season Ticket Loan for London travel
  • Salary exchange nursery fee scheme
• • Life Insurance
  • Healthcare platform including:
    • Cashback on dental, optical & physio
    • Virtual GP access
    • Mental health and stress support helplines
    • Additional wellbeing resources
• • Enhanced parental leave
  • Cycle to work scheme
  • Flexible benefits that support everyday life
• • Career development and progression tools
  • Opportunities to grow within a fast‑scaling international business

From sporting events and pub nights to seasonal celebrations and socials, we make time to connect and celebrate together.

Diversity & Inclusion

We believe that diversity and inclusion are essential to our success. We are committed to fostering a culture where everyone feels valued and respected, regardless of their background, identity or experiences. By embracing diverse perspectives and promoting equity, we aim to create an environment where all employees can perform and reach their full potential.

What’s next?

• We will review your application and come back to you as soon as possible.
• You must be eligible to work in the UK to be considered for this position.
• Full background checks will be carried out on all successful candidates.