Principal Android Engineer (Contract, Outside Ir35)

Hedgehog Lab; City of Edinburgh; Remote; GBP 101,000 - 138,000; Full time

Job summary

hedgehog lab is a digital product consultancy with 20 years of experience helping public and private sector organisations through digital transformation. We're B Corp and Great Place to Work certified. You'll lead a hedgehog lab delivery team working on our client's customer-facing Android app.

Our client is a well-known UK bank. This contract starts January 2027 and runs for around six months, with a remote-first setup and an on-site expectation.

Qualifications

• Senior or lead Android experience with Kotlin and Coroutines.
• Experience directing technical direction and architecture for an Android app.
• Mentoring engineers and setting team standards.
• Expertise with Jetpack Compose, XML layouts, Data Binding, and Java.
• MVVM with Hilt/Dagger, unit testing with JUnit and MockK.
• Security of data and network calls, and defect/ performance investigations.

Responsibilities

• Lead technical decisions, including moving from XML/Data Binding to Compose.
• Set coding, testing and code review standards for the team.
• Mentor senior engineers and align with client engineers.
• Collaborate with client teams on technical approach and priorities.
• Build features in Kotlin/Compose within MVVM using Hilt/Dagger.
• Ensure secure handling of data and network calls; investigate defects.

Skills

Kotlin

Coroutines

Flow

Jetpack Compose

XML layouts

Data Binding

Java

MVVM

Hilt

Dagger

JUnit

MockK

Espresso

Security

Architecture

Mentoring

Code reviews

Tools

Android Studio

CI/CD

Job description

A lot of Principal roles take you away from the code.

Here you'll lead the technical side of a hedgehog lab team delivering a UK bank's Android app as it moves to Jetpack Compose, and still build alongside them.

It's a contract outside IR35, expected to start in January 2027 and run for around 6 months. You'll work remote first, [on-site expectation]What's in it for you

You'll shape how a large banking app moves to Compose, from the approach the team takes to the standards it follows.

You'll lead a consultancy team that owns the delivery, with engineers who take testing and code reviews seriously.

You'll add regulated banking work to your CV, which carries weight on future contracts.

Who you'll be doing it for

hedgehog lab is a digital product consultancy with 20 years of experience helping public and private sector organisations through digital transformation. We're B Corp and Great Place to Work certified.

You'll lead a hedgehog lab delivery team working on our client's customer-facing Android app. Our client is a well-known UK bank.

What you'll be doing

• Leading the team's technical decisions, including architecture and the move from XML and Data Binding to Compose
• Setting coding, testing and code review standards for the team
• Mentoring the Senior engineers
• Working with the client's own engineers on technical approach and priorities
• Building features in Kotlin and Compose within an MVVM architecture using Hilt and Dagger
• Making sure sensitive data and network calls are handled securely
• Leading investigations into defects and performance issues

Experience you must have

• Commercial Android experience at a senior or lead level, in Kotlin with Coroutines and Flow
• Leading the technical direction of an Android app, including architecture decisions
• Mentoring engineers and setting standards for a team
• Jetpack Compose, plus XML layouts, Data Binding and enough Java to work on older code
• MVVM and dependency injection with Hilt and Dagger
• Unit testing with JUnit and MockK, and using tests to make safe changes in large codebases
• Mobile security, particularly protecting sensitive data and securing network calls

Experience that's nice to have

• Banking, fintech or other regulated apps
• SAFe or another scaled agile framework
• Leading a migration from XML screens to Compose
• UI testing with Espresso or Compose
• Certificate pinning, code obfuscation and root detection
• CI/CD pipelines and mobile release processes
• Accessibility experience