Role Overview
Accessible rail travel depends on systems that work reliably in live environments.
Our Passenger Assistance platform turns passenger assistance requests into coordinated action inside live rail operations.
We're hiring a Senior Mobile Engineer to lead greenfield builds and complex migrations across our real-time rail mobile systems.
Strategic Context
Transreport exists to remove structural barriers in rail travel. Our vision is that everyone has access to travel everywhere.
We operate across the UK, Japan, and the EU and have supported over 10 million assistance requests for more than 1 million users. We are a Series A company recognised with a King's Award.
As we scale internationally, this role will lead the development of a React Native application to support evolving B2B requirements while modernising our Android platform and strengthening cross-platform alignment.
Outcomes & Impact
Within 6 months, you will:
Architect and launch the first production version of our new B2B React Native application.
Provide reliable senior-level cover for the Kotlin Android codebase.
Establish clear migration principles for introducing React Native into an existing native environment.
Build trust across Data, Product, and Mobile teams as a technical bridge.
Within 12 months, you will:
Deliver a phased migration roadmap from monolithic native Android to React Native.
Reduce platform risk while increasing cross-platform feature parity.
Introduce measurable performance improvements in mobile stability and delivery velocity.
Influence long-term mobile architecture decisions across the organisation.
Responsibilities
Architect & Build - Design and ship a new React Native B2B application from scratch using TypeScript, React Navigation, and modern animation libraries. You will define architectural standards and ensure scalability from day one.
Maintain & Stabilise - Provide senior-level coverage for the existing Kotlin Android application (Clean Architecture, MVVM). Ensure stability for both staff-facing and passenger-facing applications operating in live rail environments.
Strategise Migration - Formulate and execute a safe, phased plan to deconstruct the existing monolithic Android app and rebuild functionality in React Native without disrupting current operations.
Bridge Native & Cross-Platform - Write native modules where necessary and ensure high-performance interop between Kotlin and JavaScript/TypeScript using the React Native Bridge and JSI.
Cross-Team Alignment - Work closely with the Swift/iOS engineer to ensure migration plans align with iOS architecture and roadmap priorities. Collaborate with Data and Product teams to balance commercial speed with platform stability.
This is a high-context-switching role requiring strong autonomy and decision-making capability.
The Tech Environment:
Target Stack
React Native (TypeScript)
React Navigation
Reanimated
Legacy / Native Stack
100% Kotlin
Android SDK 24–34
Jetpack
Coroutines (Flows/Channels)
Koin (Dependency Injection)
MockK
Gradle Kotlin DSL
You are not expected to know every tool immediately, but you must be comfortable operating deeply in both native Android and cross-platform React Native ecosystems.
Requirements
Must Haves
6+ years of mobile engineering experience.
Senior-level Kotlin expertise, including Clean Architecture, MVVM, DI (Koin/Dagger), and Coroutines/Flow.
Strong React Native experience beyond UI — including native modules, Bridge/JSI, and performance optimisation.
Experience integrating React Native into an existing native Android codebase (brownfield experience).
Proven experience architecting or significantly contributing to mobile platform migrations.
Comfortable making architectural trade-offs in high-risk, live environments.
Ability to manage ambiguity and switch context between greenfield and legacy projects.
Strong communication skills and experience working in remote, cross-functional teams.
Nice to Haves:
Experience migrating from fully native apps to cross-platform solutions.
Experience in transport, logistics, or regulated industries.
Familiarity with performance profiling tools on Android.
Experience working in B2B SaaS environments.
Exposure to Swift/iOS architecture (even if not hands-on).
Benefits
Private healthcare after your probation (including children)
Company pension scheme
Hybrid working model
25 days holiday
Volunteering Leave
Free flu jab for you and your family
Culture & Operating Principles
We value:
Ownership over hierarchy
Clarity over bureaucracy
Impact over job titles
We operate with high autonomy and high accountability. People are expected to raise risks early, communicate clearly, and take responsibility for outcomes.
Interview Roadmap
1. Screening Call (30 mins) – Recruiter alignment
2. Technical Architecture Discussion – Migration & RN integration deep dive
3. Deep Dive Interview – Engineering & Product
4. Final Culture Conversation – Leadership alignment
Guaranteed Interview Scheme
We're a Disability Confident employer and we welcome applications from disabled candidates. If you need any adjustments at any stage of the recruitment process, please tell us what would help - we'll work with you to make the process as accessible as possible.
We also offer a Guaranteed Interview Scheme (GIS) for candidates who consider themselves to have a disability as defined under the Equality Act 2010.
If you indicate this option in your application and your application demonstrates that you meet the essential criteria for the role, you'll be invited to interview or assessment.
Choosing GIS doesn't guarantee a job offer. If you have any questions, please get in touch.