Dotnet Developer at KDR Talent Solutions, Leeds, £425 per day

Senior .NET Developer (Financial Services) – Contract (Outside IR35)

• Role: Senior .NET Engineer
• Engagement: Contract (Outside IR35 – deliverables-focused, SDS provided)
• Duration: 6 Months initial (scope for extension)
• Location: Hybrid – Leeds City Centre (2 days per week onsite, 3 days remote)
• Day Rate: up to £425/day (depending on depth of payments/cloud experience)
• Start Date: Immediate

Project Overview

We are seeking a senior, deeply hands-on .NET Developer to join a critical, fast-moving payments resilience programme.

In this contract, you will help design and build a brand-new, Azure-hosted payment capability from the ground up. The platform handles mission-critical payment processing, resilient downstream communication, automated recovery, and robust reconciliation.

We need a pragmatic technical contractor who takes direct ownership of work streams, works closely with Architecture, Security, Cloud/DevOps, and QA, and moves swiftly from design whiteboard into production-grade C# code.

Key Deliverables & Outcomes

• Architect, build, and deploy new transactional APIs and resilient worker services using modern C# and ASP.NET Core.
• Engineer robust resilience mechanisms, including idempotency keys, duplicate-payment prevention, automated retries, circuit breakers, and dead-letter handling.
• Build backend workflows for end-of-day and real-time transaction reconciliation with external payment gateways and banking networks.
• Implement strict security best practices, configuring OAuth 2.0 / OpenID Connect, JWT validation, Azure Key Vault, and Managed Identities.
• Containerize services using Docker and target modern hosting infrastructure (Azure Container Apps / AKS).
• Configure observability, tracing, and operational alerting across transactional boundaries using Azure Application Insights and OpenTelemetry.
• Maintain rigorous test coverage through comprehensive unit, integration, and contract testing.

Required Experience & Technical Skills

• Core .NET: Deep expertise in modern C# / ASP.NET Core, asynchronous programming, clean DI patterns, and SOLID engineering fundamentals.
• Resilient Systems: Proven track record tackling the complexities of transactional systems: distributed state, concurrency, idempotency, retry policies, and fault recovery.
• Data Persistence: Advanced Entity Framework Core and SQL Server / Azure SQL skills (schema design, index optimization, distributed locking, transactional integrity).
• Modern Azure Stack: Hands-on experience with:
• Docker / Containerized microservices
• Azure Container Apps (or App Services / AKS)
• Azure Key Vault & Managed Identity (secure, secretless architecture)
• Azure Application Insights / structured distributed tracing
• Identity & Security: Solid understanding of OAuth 2.0, OpenID Connect, and token-based API security.
• Testing & Quality: Practical experience writing effective unit and integration tests (e.g., xUnit, Testcontainers, WireMock/Moq) within automated CI/CD pipelines.

Highly Desirable

• Direct domain experience in Payments, Fintech, Core Banking, or High-Volume Transaction Processing.
• Familiarity with message brokers/event streaming (Azure Service Bus, Event Hubs, or Kafka).
• Exposure to modern front-end frameworks (specifically React) for administrative/monitoring tooling.

Working Arrangements & Selection Process

• Working Pattern: Hybrid working — 2 days per week onsite in their Leeds City Centre office (short walk from Leeds Station), with 3 days remote.
• Interview Process: A concise, contractor-friendly process focused on direct technical contribution. We want to discuss systems you have personally designed, written, and debugged rather than high-level team management. Shortlisted candidates may be asked to complete a focused practical coding exercise.

To Apply

• Please submit your current CV detailing recent payments/high-resilience .NET projects, your limited company status, and your availability.