Frontend Engineer

Oscar Technology; Greater London; On-site; GBP 85,000 - 105,000; Full time

Job summary

Oscar Associates (UK) Limited is recruiting a Front‑End Engineer for our London core team. You’ll work in React, TypeScript and React Native on data‑dense enterprise surfaces and AI‑assisted workflows.

Based in Kings Cross, London, the role is on-site three days a week with visa restrictions not available. You’ll contribute to a shared component library, ship high‑quality interfaces and maintain strong testing and accessibility standards.

Qualifications

• 5+ years in front-end engineering with React and TypeScript.
• Experience shipping data-dense enterprise interfaces.
• Strong state management and front-end security knowledge.
• Proven testing discipline with modern tooling.
• Experience building SaaS or multi-tenant products.
• Daily use of AI coding tools.

Responsibilities

• Build advanced forms, analytics dashboards, real-time updates and rich document views in React and React Native with TypeScript.
• Make dense data usable through grid components such as AG Grid or MUI DataGrid, virtualisation and CSS Grid/Flexbox layouts that hold at scale.
• Implement streaming responses, citations, verification affordances and safe failure states.
• Make approvals, hand-offs, tool calls and partial progress visible in agent workflows, and let users interrupt or correct a run.
• Work on perceived performance so model calls taking seconds still feel responsive.
• Contribute to the component library and tenant theming, keeping branding, permissions and configuration clean.
• Integrate back-end APIs with authentication, role-based access, tenant context and useful client-side error handling.
• Maintain unit, integration and end-to-end tests with Jest, React Testing Library and Cypress or Playwright.
• Meet WCAG 2.1 accessibility standards.
• Profile and optimise code splitting, lazy loading, memorisation and bundles through Jenkins and SonarQube pipelines to AWS.

Skills

React

TypeScript

Frontend architecture

Testing

Security (XSS/CSRF/CSP)

CI/CD

AI coding tools

Multi-tenant SaaS

Data-dense interfaces

Education

Engineering/CS degree or equivalent

Tools

Jest

React Testing Library

Cypress

Playwright

Git

AWS

Module Federation

Job description

Frontend Engineer

Location: Kings Cross, London

Salary: £85,000-105,000

Contract: Permanent

Working pattern: On site, 3 days a week

A new software venture built inside an established global provider of analytical and research services to the private capital industry is hiring Front‑End Engineers to build the interfaces investment professionals use to inspect data, work with documents and direct AI agents. You’ll join the UK core team of around thirty people, working in React, React Native and TypeScript on data‑dense enterprise surfaces and AI-assisted workflows. The role sits within a nine-person engineering cohort being hired across front‑end and back‑end, reporting to the Head of Engineering.

THE ROLE

You’ll report to the Head of Engineering and contribute to a shared component system that can be themed across tenants. The work combines data‑heavy enterprise interfaces with the performance and interaction design that AI‑assisted workflows demand.

• The hard part is trust and clarity: users need to check an answer quickly and follow a long‑running workflow while it is still in progress.
• Part of a nine‑person engineering cohort being hired across front‑end and back‑end.
• Based with the UK core team of around thirty people in Kings Cross, alongside colleagues in London and India.

WHAT YOU’LL BE DOING

Your remit spans the product surfaces, the AI experience, the shared platform and the quality bar.

• Build advanced forms, analytics dashboards, real‑time updates and rich document views in React and React Native with TypeScript.
• Make dense data usable through grid components such as AG Grid or MUI DataGrid, virtualisation and CSS Grid/Flexbox layouts that hold at scale.
• Implement streaming responses, citations, verification affordances and safe failure states.
• Make approvals, hand‑offs, tool calls and partial progress visible in agent workflows, and let users interrupt or correct a run.
• Work on perceived performance so model calls taking seconds still feel responsive.
• Contribute to the component library and tenant theming, keeping branding, permissions and configuration clean.
• Integrate back‑end APIs with authentication, role‑based access, tenant context and useful client‑side error handling.
• Maintain unit, integration and end‑to‑end tests with Jest, React Testing Library and Cypress or Playwright.
• Meet WCAG 2.1 accessibility standards.
• Profile and optimise code splitting, lazy loading, memorisation and bundles through Jenkins and SonarQube pipelines to AWS.

WHAT WE’RE LOOKING FOR

• 5+ years in front‑end engineering with deep React and TypeScript experience.
• Experience shipping data‑dense enterprise interfaces, with the ability to explain the grids, dashboards and state decisions behind them.
• Strong grasp of state management and front‑end security, including XSS, CSRF and CSP.
• Solid testing discipline.
• Experience building SaaS or multi‑tenant products, with Git, CI/CD and cloud deployment.
• Daily use of AI coding tools such as Cursor or Claude Code, and a considered view of where they help.
• A degree in engineering, computer science or a related field, or equivalent experience.
• React Native experience is valued.

NICE TO HAVE

• Interfaces for AI‑assisted or agentic products.
• Micro‑frontends, including Module Federation or comparable approaches.
• Contribution to or ownership of a design system.
• Financial data visualisation.

THE REALITY

This will be difficult, and it demands pace and accuracy.

• Autonomous systems are being built inside high‑stakes live businesses, where decisions carry real consequences and waiting for everyone to agree is not always an option.
• The systems will sometimes get things wrong; in this phase the London team needs to create the evaluations, visibilities and safeguards that catch mistakes early and stop the same failures recurring.
• The goal is to build the foundations of an enterprise‑grade technology platform serving a multi‑billion dollar serviceable market, and to share in that growth.

IN OUR CONVERSATIONS

Come ready to discuss three pieces of work:

• A data‑dense interface you shipped: the state, performance and usability decisions.
• An interaction that helped users understand or verify a result.
• A quality or accessibility problem you found and the improvement you made.

LOCATION & WORKING PATTERN

• Kings Cross, London. In office 3 days a week.
• Colleagues based in London and India.
• Visa sponsorship is not available for this role.
• The interview process is intended to complete within three weeks, and adjustments to interviews can be arranged on request.

Oscar Associates (UK) Limited is acting as an Employment Agency in relation to this vacancy.

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