Senior Mobile Developer (Flutter) - Lead Architecture and Development

Please note: We are not open to contact from recruitment agencies or consultants for this role. We are also only considering UK or European-based developers — please do not apply if you are based outside this region.

About us

Hi, I'm Pete Winter, CTO for the company hiring this role. I'm hiring on behalf of an early-stage startup building infrastructure for member-owned digital communities - trusted, validated online spaces that don't monetise their members' data or attention. We believe the next generation of online communities won't be built on advertising or engagement extraction, but on validated membership, private interaction, and shared governance.

Our first product is a private messaging service for a specific professional community, launching in the UK and expanding internationally. Further details about the company and product will be shared under NDA during the interview process.

The role

You'll be taking over lead control of our mobile codebase from the external development agency that built the initial version. Your first job is to get under the hood - analyse what's there, identify what's solid and what needs rework, and set the technical direction from here on.

From there, you'll work with the CTO to lead the architecture and ongoing development of our flagship mobile app - and set the technical foundations for every product that follows on our infrastructure. You'll own the mobile codebase end-to-end, work directly with the founders on product decisions, and shape how a privacy-first messaging product gets built on Flutter.

You'll be working on a product where trust is the entire proposition. Identity validation, private messaging, member data sovereignty, and a credentialed user base mean the technical bar is high and the stakes are real.

Location

This role is fully remote, and we're looking for a UK / European-based developer.

What you'll do

• Take over the existing Flutter codebase from our development agency, audit its architecture, code quality, and technical debt, and produce a clear plan for what to keep, refactor, or rebuild
• Lead all subsequent architecture and delivery of the mobile app on Flutter, targeting iOS and Android from a single codebase
• Make the core technical decisions on state management, real-time messaging, offline behaviour, and the encryption/privacy stack
• Continue to build on our integration with our backend services, which are managed through a Python/Django administration system, for identity validation, registration, and messaging
• Integrate third-party APIs and AI/LLM models to enrich and improve our database and member experience
• Establish engineering practices — CI/CD, testing, release processes, code review — that will scale as the team grows
• Partner closely with the CTO, founders, designers, and backend team on product and infrastructure decisions
• Lay the groundwork for a multi-product architecture where the first app is one of several to be built on shared infrastructure

What we're looking for

• 6+ years building production mobile applications, with at least 3 years shipping Flutter apps to the App Store and Google Play

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• Strong Dart fundamentals and deep familiarity with Flutter's rendering, animation, and platform channel layers
• Demonstrable experience inheriting and improving existing codebases — auditing, refactoring, and bringing engineering standards up without rewriting from scratch unnecessarily
• Solid grasp of mobile security, secure storage, and at least working knowledge of end-to-end encryption patterns
• Experience integrating real-time messaging (WebSockets, push notifications, background sync)
• Experience consuming REST and/or GraphQL APIs from a Python/Django backend
• Strong understanding of working with third-party APIs, and practical experience integrating AI/LLM models (OpenAI, Anthropic, or similar) into production applications
• Comfort owning a codebase end-to-end, including testing, CI/CD, and release management
• Native iOS or Android experience is a strong plus — you'll occasionally need to drop into platform code
• Excellent written communication
• Available to commit to the role full-time

What we offer

• Competitive salary, benchmarked to your location
• A great opportunity to join a company at an early stage, with big plans for future development both in the UK and globally
• A genuinely meaningful product with real users who need it
• Direct ownership of architectural decisions, not implementing someone else's spec