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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Mobile Architect - Outside IR35 - **Company:** Hydrogen - **Location:** London, UK - **Salary:** £208,000.0 - £234,000.0 - **Contract:** Temporary to permanent - **Skills:** Application Programming Interfaces (APIs), Apple Xcode, Architectural Patterns, Confluence, Profiling, Online Banking, Gradle, Mobile Application Software, Model View ViewModel, OAuth, OpenID, Session Management, UML, Management of Software Versions, Uikit, Swiftui, Swift (Programming Language), Backend, Kotlin, Modularization, Jetpack Compose, Graphql, React Native, Interactive Whiteboards, Api Gateway, Grpc, Multiplatform - **Published:** September 18, 2026 - **Apply:** https://www.reed.co.uk/jobs/mobile-architect-outside-ir35/57362386 ## About the Role My client is looking for an experienced mobile architect to join their team on an initial 8 week piece of work with a good possibility to extend. This is a hybrid role and is outside of IR35. Able to reconstruct architecture of large existing systems from code, interviews and incomplete artefacts - demonstrable, with examples; Fluency in structured modelling approach (C4, arc42, UML, ADRs). Documentation-as-code tooling, diagramming tools, Confluence/Miro. Defining architecture characteristics and quality attributes, and assessing a system against them. Platform bias: iOS depth expected. Must be conversant enough in Android to challenge and review docs and assessment findings. iOS (primary depth) * Swift, UIKit and SwiftUI in large production apps; understands the realities of a mixed UIKit/SwiftUI estate * Modularisation at scale: SPM, Xcode workspaces, Tuist/XcodeGen, XCFrameworks, module boundary and dependency management * Hands-on experience of architectural patterns in large production apps (MVVM, VIPER, TCA, Clean-style layering), and the ability to identify which one a codebase follows; * Build, signing and distribution mechanics; profiling and performance analysis Android (working knowledge) * Kotlin, Jetpack Compose, Gradle multi-module builds: enough to read, question and validate, not necessarily to write Backend, API and integration * Mobile-to-backend integration patterns: BFF, API gateway, REST/GraphQL/gRPC, versioning and contract management * Identity and authorisation: OAuth 2.0, OIDC, token lifecycle, session management, step-up authentication; FAPI and Open Banking awareness * Understanding of how a bank's mobile app sits on top of core banking, payments and legacy estates, including mainframe-fronted services Essential non-technical skills * Executive stakeholder management: can hold a room with CTO-level stakeholders, present findings without softening them or turning them into an accusation * Elicitation under resistance - gets useful answers from people who suspect they are being assessed * Written clarity for mixed audiences * Scope discipline: recognizes rabbit holes early and closes them protecting a fixed-price approach * Independent judgement: willing to state a conclusion on partial evidence, and to label clearly where confidence is low * Pace: comfortable producing a defensible first cut in week two for discussion and refining, rather than perfecting until week seven * Fluent professional English, spoken and written Nice to have * Prior delivery inside a UK or EU retail bank, or comparably regulated environment * Experience of a mobile platform modernisation or re-platforming programme, in either direction * Cross-platform estates: Kotlin Multiplatform, React Native, hybrid/webview components * Consultancy background; experience scoping and defending fixed-price work ## Related Videos - [SwiftUI In Production](https://www.wearedevelopers.com/videos/134-swiftui-in-production) - [Scalable architecture for mobile apps](https://www.wearedevelopers.com/videos/275-scalable-architecture-for-mobile-apps) - [Exploring the Power of gRPC-Gateway for Writing RESTful Services](https://www.wearedevelopers.com/videos/2072-exploring-the-power-of-grpc-gateway-for-writing-restful-services) - [ChatGPT and Java: A Match Made in Heaven or Hell?](https://www.wearedevelopers.com/videos/536-chatgpt-and-java-a-match-made-in-heaven-or-hell) - [There's an app for that - on the role of cross platform development in the app development ecosystem](https://www.wearedevelopers.com/videos/278-there-s-an-app-for-that-on-the-role-of-cross-platform-development-in-the-app-development-ecosystem) - [Unsolved mysteries between Usability and Accessibility in iOS](https://www.wearedevelopers.com/videos/737-unsolved-mysteries-between-usability-and-accessibility-in-ios) ## Related Articles - [Cross Platform Mobile Development Frameworks to Use in 2025](https://www.wearedevelopers.com/magazine/404-cross-platform-mobile-development-frameworks-to-use-in-2025) - [Fully Remote Software Engineer Jobs](https://www.wearedevelopers.com/magazine/447-fully-remote-software-engineer-jobs) - [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers) - [7 Most Popular Web Developer Jobs in Europe](https://www.wearedevelopers.com/magazine/163-7-most-popular-web-developer-jobs-in-europe) - [The Most Popular IT Jobs on the Market](https://www.wearedevelopers.com/magazine/376-the-most-popular-it-jobs-on-the-market) - [Is Software Engineering Over-Saturated?](https://www.wearedevelopers.com/magazine/418-is-software-engineering-over-saturated)