Senior Flutter Engineer

AJ Bell; Greater London; Hybrid; GBP 90,000 - 120,000; Full time

Benefits offered by this job

26 days holiday

Pension 7%

Discretionary bonus

Share schemes

Health plan

Onsite gym

Enhanced family leave

Travel and bike loan

Employee assistance

Job summary

AJ Bell in London seeks an experienced Senior Flutter Engineer to replace existing native apps and power a D2C platform used by hundreds of thousands of customers. You will build a high-quality Flutter app with a focus on UX, accessibility, and performance.

You will work in a hybrid setup with at least 50% time in the office, contribute to architecture decisions and code reviews, and mentor teammates to raise engineering standards across the mobile stack.

Qualifications

• Shipped production mobile apps with end-to-end release cycles.
• Experience with CI/CD pipelines and release management.
• Strong focus on accessibility and inclusive UX.
• Ability to document designs for technical and non-technical audiences.

Responsibilities

• Architect solutions with the team and write technical documents.
• Write well-structured, testable Flutter code and review peers.
• Unblock teams, drive architectural decisions, and maintain code quality.
• Ensure accessibility remains a core consideration in UI.
• Mentor teammates through pairing and PR reviews.

Skills

Flutter

Mobile DevOps

Code reviews

Architecture

AI coding tools

Debugging

Design system

Job description

We are searching for an experienced Senior Flutter Engineer to work in a product centric role, helping us bring feel good investing to life. You will help build the Flutter app that is replacing our long-standing native iOS and Android apps, serving a D2C business of over 500,000 customers, a large proportion of whom manage their investments through the app. You will put users at the forefront of the way you think and be passionate about great user experience and user interface design. You will be able to deliver tested, resilient, and performant code against a fast-paced environment. Your role will be pivotal in helping us achieve our mission by developing, shaping, and iterating our customer facing Flutter applications. We work hybrid, with at least 50% of your time in the office.

What does the job involve?

This is a hands-on individual contributor role in a cross functional team. You won't line-manage, but you will have a strong influence on how the team builds — through pairing, code review, mentoring and the technical standards you set.

• Architect solutions with your team and write the technical documents that define what we're building.
• Write well-formulated, testable and readable code using appropriate software paradigms.
• Multiply the team's output — unblock others, make the difficult architectural calls, and leave the codebase easier to work in than you found it.
• Ensure accessibility is at the forefront of our approach.
• Mentor and develop others in the team, through pairing, reviewing pull requests, and advocating development standards to be followed by existing and new team members.

How we build

We care more about how you think than which packages you've used, but this is the shape of the work.

• A Flutter monorepo — one app plus a set of internal packages.
• Layered Clean Architecture, enforced in CI.
• A design system built from Figma design tokens and catalogued in Widgetbook.
• A backend-for-frontend that drives parts of the UI, so screen composition can change without an app release.
• GitHub Copilot for every engineer, with repo-level instructions and custom skills we've built to keep AI output aligned with our architecture and patterns.

Competence, knowledge and skills

Technical skills

You've shipped production mobile apps to real customers through full app store release cycles, and you're the engineer others turn to for architecture decisions and code review. Your Flutter experience might come from production work, or from a strong native background plus substantial Flutter projects.

• Strong understanding of mobile DevOps practices, including CI/CD pipelines, release management, and app store deployment processes.
• Advanced software engineering skills, including writing high-quality code, conducting thorough code reviews, and proactively identifying anti-patterns and maintainability risks.
• Comfortable using AI coding tools to work faster, with the judgement to know when to rely on them and when not to. You own the code you ship, however it was produced.
• Proven ability to diagnose, troubleshoot, and resolve defects across the mobile application lifecycle.
• Solid knowledge of reactive state management patterns and how to apply them in mobile architectures.
• Strong grasp of software architecture principles, with the ability to communicate and document designs clearly for both technical and non-technical audiences.
• Experience building products on top of a design system — consuming and extending shared components rather than reinventing them, and knowing when something belongs in the shared library rather than in your feature.

How you work

• Strong passion for mobile UX and building inclusive products, with working knowledge of accessibility best practices and relevant standards.
• A clear communicator who listens well and collaborates deliberately across product, design and engineering — comfortable working autonomously, and equally comfortable inside a cross-functional team.
• High ownership: you turn ambiguous problems into shipped solutions, prototyping early to validate ideas, and take the initiative on improvements rather than waiting to be asked.

Nice to have

• Native Android (Kotlin) or iOS (Swift) experience. Our legacy native apps are still live, and a native background helps when working out what existing behaviour we need to carry across.
• Experience working in finance, investing, or another regulated domain.
• Experience with backend-for-frontend architectures, where the backend shapes what the app renders.
• Experience building or owning a design system or shared component library.

About us:

At AJ Bell, we believe investing should feel good. Whether you're looking for an ISA, pension or dealing account, whether you want to invest with the help of a financial adviser or do it yourself, we have easy-to-use solutions to suit people from all walks of life.

We're one of the UK's fastest-growing investment platform businesses, trusted by everyone from professional financial advisers to first-time investors.

Today, over 762,000customers trust us to manage more than £121.5billion of assets. By continually striving to make investing simpler and more accessible, we're helping more people take control of their financial futures.

We're proud to be recognised as one of the UK's Best 100 Companies to Work For for six consecutive years, and a Great Place to Work in 2025 and 2026, a reflection of our supportive and collaborative culture.

What we offer

• 26days holiday, increasing with service + buy/sell scheme + bank holidays
• 7% Pension with matched contributions
• Discretionary bonus scheme
• Share schemes (including free shares and BAYE)
• Health Cash Plan and discounted private healthcare
• Free onsite gym
• Enhanced family leave (subject to qualifying criteria)
• Travel and bike loan schemes
• Employee Assistance Programme

Life at AJ Bell

• Regular social events including summer and Christmas parties
• Learning and development opportunities tailored to you
• Casual dress code
• Friendly, supportive team environment

Our ways of working

We offer hybrid working, with a minimum of50% of your working time per monthspent in the office. For new starters, there’s an initial period of full-time office working to help you settle in and build relationships.

Inclusion & diversity

We’re committed to creating an inclusive environment where everyone feels respected and able to be themselves at work. We welcome applications from all backgrounds and make hiring decisions based on skills, experience and potential.