Senior Software Engineer

Hybrid – London | 2–3 days per week in office

Immersum is partnering with a global payments business looking for a Senior Software Engineer to join their Banking & FX team, working on the systems responsible for moving client money across payments, FX, reconciliation and banking integrations.

This is a hands on role for a strong .NET engineer who enjoys working on complex, high-reliability systems where getting it right really matters.

The Role:

• Build and own production services using .NET 10 and Azure
• Develop asynchronous, event-driven systems that handle failures, retries, timeouts and duplicate messages
• Work across payments, FX, ledgers, reconciliation and banking integrations
• Integrate with banks and payment schemes
• Make architectural decisions and own your services from development through to production
• Build security, reliability and observability into systems from the start
• Use Grafana, Application Insights and Claude Code as part of the engineering workflow

What We’re Looking For:

• Strong commercial experience with .NET / C#
• Experience building and running production services in the cloud
• Strong understanding of asynchronous and event-driven systems
• Experience with Azure , or AWS/GCP
• Strong SQL Server experience and familiarity with EF Core
• Good testing and software engineering fundamentals
• Experience working with security, reliability and observability
• Comfortable working in a regulated environment
• Strong communication skills and the confidence to challenge technical decisions

Why Join:

• Work on critical systems responsible for moving client money
• Genuine ownership over the services you build
• Modern .NET 10, Azure and AI tooling environment
• Autonomous engineering team with real influence over technical decisions
• Competitive benefits including 25 days' holiday + bank holidays, bonus, pension, healthcare and enhanced parental leave.

Please note this role requires full right to work in the UK.