Tier 1 Bank - .NET CORE / React / Banking / Architecture
Role - C# Developer / .NET Core Duration - 6 months with very likely extensionLocation - Hybrid / Canary Wharf - 3 days per week in a Canary Wharf office
Rate - £415 p/d inside IR35
Tech Stack
C#
.NET Core
SQL / Oracle
React / Typescript Role
Deliver, modernise, and support business-critical applications, frameworks and services across our stack (.NET Framework/.NET Core, HTML/CSS/TypeScript/React, Python, SQL Server, Oracle). The role focuses on refactoring legacy systems to reduce technical debt, improve reliability and performance, and embed modern security patterns across the service estate.
Tasks
Design, build, and maintain server-side and client-side software using .NET (Framework/Core), React/TypeScript, Python, and relational databases (SQL Server, Oracle); contribute to API and UI development, data access layers, and integration points.
Refactor and modernise legacy codebases: modularisation, dependency updates, performance tuning, improved observability, and raising automated test coverage within CI/CD.
Embed modern security patterns and controls across web services: strong authentication/authorization (e.g., OAuth2/OpenID Connect), token-based access, secure session management, least privilege/role-based access, mTLS/TLS hardening, secure secrets handling, input validation and output encoding (OWASP), dependency vulnerability remediation, and policy enforcement via gateways.
Participate in greenfield projects: design and implement new applications and services, ensuring scalability, maintainability, and security from inception.
Database engineering: optimise queries and schemas, implement safe migrations, and tune performance for SQL Server and Oracle workloads.
Quality and release discipline: write and maintain unit/integration tests, participate in code reviews, and adhere to Change Management Control procedures for approvals and production updates.
Operations and collaboration: investigate incidents, diagnose production issues, contribute to runbooks and documentation;GCS is acting as an Employment Business in relation to this vacancy