Senior Full Stack Developer
Summary
Senior Full Stack Developer on a 6-month Inside IR35 contract (via staffing firm Insight Global) at a global financial markets organisation in London, modernising business-critical index management platforms. Day-to-day work spans C#/.NET backend services, APIs, SQL Server databases, and Angular frontends, including legacy migration work.
Insight Global are seeking a Senior Full Stack Developer to join a leading global financial markets organisation, supporting a Frontier AI Cyber Remediation team focused on modernising and enhancing business-critical index management platforms.
This position requires 3 days onsite in London, UK for a 6-month initial contract through March 2027 and is Inside IR35.
As a Senior Full Stack Developer, you will be responsible for designing, developing, and enhancing applications that support the migration and management of critical financial data platforms. Working across backend services, APIs, databases, and modern user interfaces, you will collaborate closely with product teams, business stakeholders, and engineers to deliver scalable, secure, and reliable solutions. You will also play a key role in platform modernisation initiatives, troubleshooting complex technical issues, and improving application performance and quality.
Must-Have Requirements Include:
- Strong hands-on development experience with C# and .NET
- Experience with frontend development using Angular
- Experience building and supporting APIs and backend services
- Experience developing enterprise web applications across both frontend and backend technologies
- Working knowledge of Microsoft SQL Server and T-SQL
- Ability to investigate and resolve complex application, data, and business issues independently
- Experience supporting platform migration, transformation, or modernisation initiatives
- Experience leveraging AI tools within the software development lifecycle
- Strong communication, stakeholder management, and problem-solving skills
Plusses Include:
- Experience working with AWS or cloud-hosted applications
- Knowledge of AWS services such as EC2 and Lambda
- Experience modernising or migrating legacy .NET applications
- Experience working with microservices architectures and RESTful APIs
- Exposure to CI/CD pipelines and automated deployment processes
- Experience with Infrastructure as Code tools such as Terraform
- Experience working with financial, market, or benchmark data
- Understanding of index calculations, configurations, or lifecycle management
- Experience analysing and reconciling historical datasets
- Experience working within highly secure, business-critical enterprise environments
- Financial Services or Capital Markets industry experience
If you're an experienced Full Stack Developer looking to contribute to large-scale modernisation initiatives within a global financial services environment, we'd love to hear from you.