Senior Frontend Developer (React Native)

6 Month contract
40 hours per week
Inside IR35
Hybrid 1 office day

London Farringdon office address: 47-53 Charterhouse St, London, EC1M 6PB

About the Role

We are looking for a highly experienced Senior Frontend Engineer to join a fast-paced and innovative engineering environment, helping to build and scale next-generation digital products and customer experiences. This is an opportunity to work on complex, high-impact applications used by both customers and internal stakeholders, while influencing technical strategy and engineering best practices.

As a senior member of the engineering team, you will take ownership of critical frontend systems, mentor engineers across multiple levels, and drive technical decisions that balance business value with long-term maintainability.

Key Responsibilities

• Lead the planning and delivery of complex frontend projects, translating ambiguous requirements into clear technical solutions.
• Take end-to-end ownership of critical applications, ensuring reliability, scalability, performance, and maintainability.
• Drive technical decision-making and architecture discussions across the team.
• Balance short-term business priorities with long-term technical health and sustainability.
• Manage technical debt strategically and advocate for continuous improvement initiatives.
• Deliver high-quality, production-ready code that is secure, performant, maintainable, and well-tested.
• Lead incident management and troubleshooting activities, implementing preventative measures to improve platform stability.
• Design systems with strong observability, scalability, and operational resilience.
• Create and maintain technical documentation, runbooks, and operational processes.
• Mentor and support engineers through coaching, code reviews, and technical guidance.

Required Skills & Experience

Technical Skills

• Expert-level knowledge of React, TypeScript, and modern frontend architectures.
• Strong understanding of React internals, Server Components, and modern React frameworks including js.
• Deep expertise in state management and data-fetching patterns.
• Proven experience optimising frontend performance and improving Core Web Vitals.
• Strong testing background across unit, integration, and end-to-end testing frameworks.
• Knowledge of accessibility standards, including WCAG 2.1 AA.
• Experience implementing frontend security best practices
• Strong debugging and monitoring experience using observability tools.
• Experience designing and maintaining CI/CD pipelines and deployment processes.
• Understanding of build optimisation and module bundling techniques.

Experience

• Minimum 5 years' commercial experience in frontend engineering or a similar software engineering role.
• Proven track record of delivering complex digital products within agile development environments.

Desired Behaviours

• Strong ownership mentality and accountability for product and system performance.
• Ability to communicate complex technical concepts to both technical and non-technical stakeholders.
• Collaborative approach with experience influencing teams and driving consensus.
• Passion for mentoring and developing other engineers.
• Data-driven decision-making and a pragmatic approach to problem solving.
• Commitment to inclusive, high-performing team cultures.

Technology Stack

Frontend

• React
• js
• TypeScript
• React Native
• Flutter/Dart
• Gatsby

State Management

• Redux Toolkit
• Zustand
• MobX
• TanStack React Query
• SWR
• Apollo Client

UI & Design Systems

• Tailwind CSS
• Styled Components
• Material UI (MUI)
• Radix UI
• Framer Motion
• Custom Design Systems

APIs & Data

• GraphQL
• REST APIs
• Contentful CMS
• React Hook Form
• Zod

Testing

• Vitest
• Jest
• Testing Library
• Playwright
• Storybook
• MSW
• Axe / Pa11y

DevOps & Infrastructure

• AWS
• Terraform
• GitLab CI
• Vercel
• OpenTelemetry
• Sentry
• New Relic

Please note:

Should your application be successful, and you are offered the role, a number of pre-employment checks need to be carried out before your appointment can be confirmed. Any assignment offer with our client will be subject to a satisfactory checking report from the Disclosure Barring Service.

This vacancy is being advertised by Rullion Ltd acting as an employment business.

Since 1978, Rullion has been securing exceptional candidates for a range of clients; from large well-known brands, to SMEs and start-ups. As a family-owned business, Rullion’s approach is credible and honest, focused on building long-lasting relationships with both clients and candidates.

We celebrate and support diversity and are committed to ensuring equal opportunities for both employees and applicants.