Mobile Architect - Outside IR35 in London

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.
• 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.