Senior Full Stack Engineer

Salary: £72,000 - 97,000 per year

Requirements:

• Ideally 7+ years of commercial development experience with C# / .NET / .NET Core
• Front-end coding ability with JavaScript, CSS, HTML, and React
• Good understanding of SOLID principles, Event Driven Architecture (EDA), and Domain-Driven Design (DDD)
• Experience of RESTful API design
• Experience of Azure cloud development, with a cloud-first approach
• SQL skills
• Good foundation in Test-Driven Development (TDD) methodologies, including writing and maintaining test cases using one or more of NUnit, Microsoft.TestFramework, SpecFlow, and Selenium
• Emotional intelligence, including active listening and thoughtful problem-solving
• Proactivity and the ability to demonstrate initiative positively and collaboratively
• Excellent verbal and written communication skills, including the ability to communicate technical information to technical and non-technical stakeholders
• Ability and enthusiasm to coach and guide junior engineers

Responsibilities:

• Play an active role in an Agile software team, fostering best practice and automation to ensure software quality
• Work collaboratively as a subject matter expert in our domain
• Build new features and deliver a high-quality, resilient product
• Help improve our software engineering processes and practices
• Influence our software architecture
• Partner with relevant teams across the organisation to identify how technology can solve business challenges
• Answer how and why technology is designed and delivered
• Act as a team player who is approachable and a positive role model

Technologies:

• API
• Azure
• C#
• Cloud
• CSS
• DDD
• JavaScript
• React
• SQL
• Selenium
• SpecFlow
• TDD
• ASP.NET
• DevOps
• Support
• Fullstack

More:

We are Flagstone, an online savings platform helping individuals, businesses, and charities manage, protect, and grow their cash. We are a diverse, inclusive, and collaborative team with a strong culture of kindness, respect, and growth, and we are a thriving, profitable business where smart people do their best work. This is a Senior Full Stack Engineer contract role in our Engineering department, based in our London office with a hybrid working arrangement. We offer the opportunity to work on large-scale projects in a Microsoft and Azure cloud environment while helping us revolutionise the savings market.

last updated 35 week of 2026