Senior Full Stack Engineer (React Native / .NET)

Avios Group (AGL) Limited; Greater London; On-site; GBP 60,000 - 80,000; Full time

Job summary

Avios Group (AGL) Limited is seeking a Senior Full Stack Engineer to deliver complex features for the Avios App. You will work on both mobile and backend systems, utilizing your deep expertise in React Native or .NET/C# while collaborating with a high-performing team.

This hybrid role requires you to work in our London office at least two days per week. We're looking for someone who is comfortable taking ownership from ideation through delivery and review.

Qualifications

• Strong experience delivering customer-facing applications at scale.
• Deep expertise in either React Native or .NET/C#, hands-on experience in the other.
• Experience delivering features end-to-end across mobile and backend systems.

Responsibilities

• Deliver end-to-end features across the Avios App using React Native and .NET/C#.
• Collaborate with teammates to produce production-ready solutions.
• Support the team through code reviews and mentoring.

Skills

React Native

.NET/C#

APIs

Distributed systems

Cloud environments (AWS preferred)

CI/CD

Automated testing

Mentoring engineers

Job description

About the role

We are looking for a Senior Full Stack Engineer to lead the delivery of complex, high‑impact features across the Avios App's mobile and backend systems. You should have deep expertise in either React Native or .NET/C#, with solid hands‑on experience in the other, enabling you to operate confidently across the full stack.

Responsibilities

• Deliver end‑to‑end features across the Avios App, building scalable, reliable solutions using React Native and .NET/C#.
• Collaborate with teammates across engineering, QA, Product Managers and Designers to break down complex problems and produce production‑ready solutions.
• Apply strong technical judgement to shape implementation approaches, challenge decisions where necessary, and maintain high standards of quality, performance and maintainability.
• Support the wider team through code reviews, mentoring, and continuous improvement of engineering practices.
• Identify opportunities to improve scalability, reliability and developer experience, fostering a culture of ownership and continuous improvement.

Qualifications

• Strong experience delivering customer‑facing applications at scale.
• Deep expertise in either React Native or .NET/C#, and hands‑on experience in the other.
• Experience delivering features end‑to‑end across mobile and backend systems.
• Clear understanding of how mobile and backend systems interact in a production environment.
• Strong understanding of APIs, distributed systems and cloud environments (AWS preferred).
• Experience with CI/CD, automated testing and modern engineering practices.
• Ability to contribute to technical discussions and influence implementation decisions.
• Experience mentoring engineers and raising engineering standards.
• Strong communication and collaboration skills.

What we might not be right for you if

• You only want to focus on your to‑do list; we’re a small, high‑performing team that helps each other succeed.
• You value perfection over fast iteration and progress; IAG Loyalty moves fast, learning and iterating as we go.
• You’re looking to create but not build; this is an end‑to‑end role, so you need to be comfortable owning your space from ideation through delivery and review.

Location & Working Arrangement

This role will work as part of our Loyalty Division and is based out of our London office. The team follows a hybrid model (The Blend), requiring employees to spend at least two days per week in the office, with the rest of the time working from home. You may also be required to work from one of our other office or partner locations, based on your role and responsibilities.