Senior Flutter Engineer

Job Description

Build the investing experience people rely on.

At AJ Bell, we believe investing should feel good. For many of our customers, our app is one of the main ways they manage their investments, so creating an experience that feels simple, intuitive and dependable really matters.

We're looking for an experienced Senior Flutter Engineer to help shape the next generation of our customer-facing mobile experience. You'll be part of the team building our Flutter app, which is replacing our long-standing native iOS and Android applications and serving a D2C business of more than 500,000 customers.

This is a hands-on, product-centric role where you'll help turn customer needs into great mobile experiences. You'll care about how things look and feel, as well as how they work, and you'll build tested, resilient and performant software that customers can rely on.

You'll work closely with Product, Design and Engineering to develop, shape and iterate the app, bringing technical expertise and a user-first mindset to the decisions we make.

What you'll do

Build experiences customers can rely on

• Architect solutions with your team and write clear technical documentation that defines what we're building and why.
• Write well-structured, readable and testable code using appropriate software engineering principles and patterns.
• Build resilient, performant and accessible mobile experiences with the customer at the centre.
• Diagnose, troubleshoot and resolve defects across the mobile application lifecycle.
• Take ownership of the quality and maintainability of the code.
• Help ensure accessibility is considered throughout our approach, rather than treated as an afterthought.

Raise the technical capability of the team

This is a hands-on individual contributor role. You won't have line management responsibility, but you'll have a strong influence on how we build through technical leadership, pairing, code review, mentoring and the standards you help establish.

• Unblock other engineers and help the team work through complex technical problems.
• Make well-reasoned architectural decisions and communicate them clearly.
• Review pull requests and provide constructive feedback that improves quality and maintainability.
• Mentor and support other engineers through pairing, knowledge sharing and practical guidance.
• Identify anti-patterns, technical risks and opportunities to improve the codebase.
• Leave the codebase and the team in a better position than you found them.

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.

What we're looking for

You've shipped production mobile applications to real customers and understand what it takes to build, release and maintain software throughout its lifecycle.

Your Flutter experience might come from substantial production Flutter work, or from a strong native mobile background combined with significant Flutter projects.

Technical skills

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

For our digital teams, that means creating technology that makes a real difference to how people manage their money. Our mobile app is an important part of that experience, and this role will have a direct influence on how hundreds of thousands of customers interact with AJ Bell.

We're proud to be recognised as a Great Place to Work® for the past two years, building on six consecutive years as one of the UK's Best 100 Companies to Work For. It's recognition we're proud of and a reflection of the supportive and collaborative culture we strive to create for our people.

What we offer

• 26 days 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 of 50% of your working time per month spent 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.

Your application, reviewed by people

We believe great hiring starts with people. That's why every application is reviewed by a member of our Recruitment team, rather than screened by AI. It may take us a few days to get back to you, but please be assured that your application will be given the time and attention it deserves.