Open to opportunities

Harold Austen-Okoronkwo

@haroldausten-okoronk

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Award-winning Senior Android Engineer focused on accessible, user-centric mobile experiences.

United Kingdom

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What I'm looking for

I seek challenging Android roles where I can lead accessible, high-performance mobile experiences, mentor engineers, and work with modern Android tech and clean architecture.

I am an award-winning Senior Android Engineer with extensive experience building B2C mobile applications and championing mobile accessibility. I have led and shipped large-scale apps like TfL Go and contributed to enterprise monitoring solutions such as ThousandEyes' Mobile Endpoint Agent.

My work emphasizes modern Android architecture, performance optimization and offline-first designs — from reducing app size and load times to integrating features like Google Wallet and scalable pagination. I mentor engineers, drive refactors to current Android tech, and consistently deliver measurable improvements in user experience and engagement.

I thrive in collaborative environments that value clean architecture, testing and accessibility, and I bring deep hands-on expertise across Kotlin, Jetpack Compose, MVVM/MVP, dependency injection and instrumentation testing to help teams ship high-quality products.

Experience

Work history, roles, and key accomplishments

Current

Senior Android Engineer

Current

Cisco ThousandEyes

Mar 2025 - Present (1 year 3 months)

Led development and refactor of the Mobile Endpoint Agent (MEPA), merging two major network-testing apps and updating the codebase to modern Android technologies to improve reliability and maintainability.

Kotlin Jetpack Compose MVI Coroutines OkHttp Retrofit Hilt

Senior Android Developer

Transport for London

May 2023 - Oct 2024 (1 year 5 months)

Led development on TfL Go, shipping Route Service Diagrams and bus service features to 1M+ monthly Android users using an offline-first MVVM architecture.

Kotlin MVVM Jetpack Compose Coroutines RxJava OkHttp Retrofit Offline First

Software Engineer - Android

Deliveroo

Jan 2022 - Apr 2023 (1 year 3 months)

Built a customer reviews page with a rating graph, added favourites and quick re-ordering, and implemented paginated order history to improve UX and retention.

Paging3 Kotlin MVVM Coroutines Hilt Koin Apollo GraphQL Paging 3 Mockito

Android Engineer

The Trainline

May 2021 - Jan 2022 (8 months)

Developed an online train-stop search reducing app size ~20% and improving load performance ~60%; integrated Google Wallet to enable ticket saving for Android users.

Java RxJava OkHttp Retrofit Picasso Offline First Firebase Mockito

Senior Software Developer

Transport for London

Aug 2018 - May 2021 (2 years 9 months)

Core developer and mentor on TfL Go from inception to global release; contributed accessibility-first features and custom Android views, helping the app reach 100,000 downloads in its first month.

Java Kotlin XML)RxJava Accessibility MVVM Espresso XML

Mobile Applications Developer

Ground Control

Oct 2016 - Aug 2018 (1 year 10 months)

Re‑vamped the flagship Android app with MVVM and clean architecture, reducing load times up to 80% on low-end devices and delivered an iOS counterpart in Swift.

Java MVVM Android Performance Swift iOS Development Accessibility Unit Testing