Senior C# Developer

Reference: RP/C#_1789489228

Contract Opportunity | Tier 1 Investment Bank | Canary Wharf

Overview

Our client, a Tier 1 Investment Bank based in Canary Wharf, is seeking an experienced C# Developer to join a strategic application modernisation programme. This role sits within a technology team responsible for evolving critical business applications, supporting a transition from legacy desktop solutions to modern web-based and cloud-enabled platforms.

The successful candidate will work across the full software development lifecycle, contributing to the enhancement of existing applications while helping shape the future-state architecture.


Key Information

Role: Senior C# Developer
Location: Canary Wharf, London (Hybrid Working)
Contract Length: 6 Months Initial Contract
Rate: £416 per day (Inside IR35)
Start Date: ASAP


The Programme

This role forms part of a wider transformation initiative focused on:

  • Modernising legacy desktop applications
  • Migrating technology platforms from on-premise infrastructure to Azure
  • Supporting the transition from desktop-based solutions to web technologies
  • Improving application performance, maintainability and scalability
  • Delivering new functionality aligned to business and regulatory requirements

The successful contractor will work closely with development teams, business stakeholders and architecture functions to deliver high-quality software solutions within a complex enterprise environment.


Key Responsibilities

  • Develop and maintain enterprise-grade applications using C#
  • Enhance and support existing WPF and WinForms applications
  • Contribute to the migration of desktop applications towards web-based architectures
  • Build and integrate APIs and backend services
  • Write efficient SQL queries and stored procedures
  • Collaborate with business analysts, architects and end users to understand requirements
  • Participate in code reviews and promote development best practices
  • Troubleshoot production issues and contribute to continuous improvement initiatives
  • Support the adoption of Azure technologies as part of the broader cloud transformation strategy

Required Skills & Experience

Essential

  • Strong commercial experience developing applications using C#/.NET
  • Proven expertise with WPF or Winforms
  • Strong SQL or Oracle development skills
  • Understanding of software design principles and development best practices
  • Experience working within complex enterprise environments
  • Experience working with Azure

Desirable

  • Experience with JavaScript
  • Exposure to React
  • Experience contributing to application modernisation programmes
  • Knowledge of Azure cloud technologies
  • Experience within Financial Services, Investment Banking or Capital Markets environments

Personal Attributes

  • Strong analytical and problem-solving skills
  • Excellent communication and stakeholder management abilities
  • Ability to work independently in a fast-paced environment
  • Collaborative mindset and willingness to mentor junior developers
  • Comfortable balancing support of legacy systems alongside modernisation initiatives

GCS is acting as an Employment Business in relation to this vacancy.

£400.00 - £416.00
Per day
GBP400 - GBP416 per day + Inside IR35
Added 15/09/2026
Reference: RP/C#_1789489228

Other similar jobs

Senior C/C++ Developer

Added 02/09/2026

Senior C/C++ DeveloperLocation: Remote (Ireland & European Union) Employment Type: Contract Experience Level: SeniorAbout the OpportunityWe are partnering with an innovative and rapidly growing technology company that is expanding its engineering team across Europe. With a strong technical culture and a globally distributed workforce, they are seeking an experienced Senior C/C++ Developer to help build and enhance high-performance software solutions.This is an excellent opportunity to join a highly skilled engineering environment while working remotely from anywhere within Ireland or the EU.The RoleAs a Senior C/C++ Developer, you will play a key role in the design, development, and optimization of critical...

Learn more

Senior Frontend Developer

Added 31/08/2026

Job SummaryWe are looking for a Full Stack Engineer with strong experience in React.js, backend development, AWS, microservices, and Kubernetes. The ideal candidate will work closely with Product, UX, and Engineering teams to build scalable, high-performance applications and services.Key ResponsibilitiesDesign and develop scalable frontend applications using React.js.Develop backend APIs and services using Node.js, Golang, and/or Python.Build and maintain microservices and distributed systems.Develop and deploy cloud-based applications using AWS.Work with Docker and Kubernetes for containerization and orchestration.Collaborate with Product Managers, UX Designers, and Engineers to deliver new features.Ensure seamless frontend and backend integration with a focus on performance and reliability.Participate in...

Learn more

Senior Ruby on Rails Support Developer

Added 24/08/2026

About the RoleWe're looking for a Senior Ruby on Rails Support Developer to join a fast-paced product engineering team. This role is focused on production support, troubleshooting, and issue resolution within a complex Rails application.You'll investigate technical issues, work with production data, and deliver practical solutions to business-critical problems. While there may be opportunities to contribute to feature development, your primary focus will be maintaining and supporting a live platform. Key ResponsibilitiesInvestigate and resolve production support issues involving application code and data.Diagnose root causes using logs, monitoring tools, and database analysis.Troubleshoot configuration issues and implement fixes.Identify, document, and resolve software...

Learn more

Senior Fullstack Developer

Added 21/08/2026

Senior Full-Stack DeveloperLocation: Hybrid (East - Flanders)Employment Type: Full-TimeAbout the OpportunityWe're partnering with an ambitious, technology-driven organisation that is building a modern, scalable digital platform with significant growth plans. As the business continues to expand, we're seeking a Senior Full-Stack Developer to take ownership of a key product and play a central role in shaping its technical direction.This is an exciting opportunity for an experienced developer who enjoys combining technical ownership with hands-on development. You will play a pivotal role in architectural decisions, product evolution, and the growth of the engineering function.Key ResponsibilitiesDesign, build, and enhance core product features across...

Learn more

Senior Frontend Developer

Added 18/08/2026

Job SummaryWe are looking for a Full Stack Engineer with strong experience in React.js, backend development, AWS, microservices, and Kubernetes. The ideal candidate will work closely with Product, UX, and Engineering teams to build scalable, high-performance applications and services.Key ResponsibilitiesDesign and develop scalable frontend applications using React.js.Develop backend APIs and services using Node.js, Golang, and/or Python.Build and maintain microservices and distributed systems.Develop and deploy cloud-based applications using AWS.Work with Docker and Kubernetes for containerization and orchestration.Collaborate with Product Managers, UX Designers, and Engineers to deliver new features.Ensure seamless frontend and backend integration with a focus on performance and reliability.Participate in...

Learn more

Senior Web Developer

Added 18/08/2026

Job SummaryWe are looking for a Full Stack Engineer with strong experience in React.js, backend development, AWS, microservices, and Kubernetes. The ideal candidate will work closely with Product, UX, and Engineering teams to build scalable, high-performance applications and services.Key ResponsibilitiesDesign and develop scalable frontend applications using React.js.Develop backend APIs and services using Node.js, Golang, and/or Python.Build and maintain microservices and distributed systems.Develop and deploy cloud-based applications using AWS.Work with Docker and Kubernetes for containerization and orchestration.Collaborate with Product Managers, UX Designers, and Engineers to deliver new features.Ensure seamless frontend and backend integration with a focus on performance and reliability.Participate in...

Learn more

Senior Frontend Developer

Added 17/08/2026

Job SummaryWe are looking for a Full Stack Engineer with strong experience in React.js, backend development, AWS, microservices, and Kubernetes. The ideal candidate will work closely with Product, UX, and Engineering teams to build scalable, high-performance applications and services.Key ResponsibilitiesDesign and develop scalable frontend applications using React.js.Develop backend APIs and services using Node.js, Golang, and/or Python.Build and maintain microservices and distributed systems.Develop and deploy cloud-based applications using AWS.Work with Docker and Kubernetes for containerization and orchestration.Collaborate with Product Managers, UX Designers, and Engineers to deliver new features.Ensure seamless frontend and backend integration with a focus on performance and reliability.Participate in...

Learn more

Senior Software Developer

Added 11/08/2026

Senior Software Developer Locations: RemoteContract DetailsContract Length: 12+ MonthsEmployment Type: ContractWork Model: Remote/HybridTravel: Minimal (up to 3 trips, primarily Seattle or Boston)Amazon Robotics is seeking a Senior Software Developer to support the development of a next-generation Quality Control platform that uses 3D cameras, IoT devices, and cloud-based machine learning to inspect robotic storage racks before deployment in Amazon fulfillment centers.This role focuses on building and productionizing AWS-based IoT data pipelines, backend services, and cloud integrations that enable reliable processing of image and video data at scale.Key ResponsibilitiesDesign and develop end-to-end data pipelines using AWS IoT Core, MQTT, Lambda, and S3.Build...

Learn more

Senior Software Developer

Added 11/08/2026

Senior Software Developer Locations: RemoteContract DetailsContract Length: 12+ MonthsEmployment Type: ContractWork Model: Remote/HybridTravel: Minimal (up to 3 trips, primarily Seattle or Boston)Job SummaryAmazon Robotics is seeking a Senior Software Developer to support the development of a next-generation Quality Control platform that uses 3D cameras, IoT devices, and cloud-based machine learning to inspect robotic storage racks before deployment in Amazon fulfillment centers.This role focuses on building and productionizing AWS-based IoT data pipelines, backend services, and cloud integrations that enable reliable processing of image and video data at scale.Key ResponsibilitiesDesign and develop end-to-end data pipelines using AWS IoT Core, MQTT, Lambda, and...

Learn more

Senior Software Developer

Added 11/08/2026

Senior Software DeveloperLocations: RemoteContract DetailsContract Length:12+ MonthsEmployment Type: ContractWork Model: Remote/HybridTravel: Minimal (up to 3 trips, primarily Seattle or Boston)Project Focus: AWS IoT, Serverless Architecture, Computer Vision Data Pipelines, Cloud Integration, and Production DeploymentJob SummaryAmazon Robotics is seeking a Senior Software Developer to support the development of a next-generation Quality Control platform that uses 3D cameras, IoT devices, and cloud-based machine learning to inspect robotic storage racks before deployment in Amazon fulfillment centers.This role focuses on building and productionizing AWS-based IoT data pipelines, backend services, and cloud integrations that enable reliable processing of image and video data at scale.Key ResponsibilitiesDesign...

Learn more

Senior Software Developer

Added 11/08/2026

Senior Software Developer (Contract) - AWS IoT & PythonLocations: RemoteContract DetailsContract Length:12 MonthsEmployment Type: ContractWork Model: Remote/HybridTravel: Minimal (up to 3 trips, primarily Seattle or Boston)Project Focus: AWS IoT, Serverless Architecture, Computer Vision Data Pipelines, Cloud Integration, and Production DeploymentJob SummaryAmazon Robotics is seeking a Senior Software Developer to support the development of a next-generation Quality Control platform that uses 3D cameras, IoT devices, and cloud-based machine learning to inspect robotic storage racks before deployment in Amazon fulfillment centers.This role focuses on building and productionizing AWS-based IoT data pipelines, backend services, and cloud integrations that enable reliable processing of image...

Learn more

Senior UI Developer

Added 11/08/2026

Design, develop, and maintain responsive, scalable frontend applications using React.js, with a strong focus on performance, accessibility, and usability.Build intuitive, high-quality user interfaces that deliver a seamless and engaging user experience across devices.Develop, maintain, and integrate backend APIs and services using Node.js, Go, or Python.Collaborate closely with Product Managers, UX/UI Designers, and Engineering teams to define, build, and deliver new features and enhancements.Partner with UX designers to ensure implemented solutions accurately reflect the intended user experience, design specifications, and requirements.Ensure reliable and seamless integration between frontend applications, backend services, and third-party systems.Design, build, and maintain microservices and distributed systems using...

Learn more

Senior FrontEnd Developer

Added 10/08/2026

ResponsibilitiesDevelop and maintain responsive frontend applications using React.js.Build intuitive, user-friendly interfaces with a focus on performance and usability.Collaborate with Product Managers, UX Designers, and Backend Engineers to deliver new features.Integrate frontend applications with backend APIs and services.Work with AWS, CI/CD pipelines, and cloud-based platforms.Participate in code reviews, testing, debugging, and performance optimization.Collaborate with UX designers to ensure designs and requirements are implemented as intended.Document technical designs, workflows, and APIs.Mentor junior developers and contribute to frontend best practices.Requirements5+ years of frontend development experience.Strong expertise in React.js, JavaScript/TypeScript, HTML, and CSS.Experience with REST APIs, Git, responsive design, and frontend architecture.Familiarity with AWS,...

Learn more

Senior Full Stack Developer - Security

Added 19/05/2026

Senior Full Stack Developer - Identity & Access ManagementPosition SummaryWe are seeking an experienced Senior Full Stack Developer to join a high-performing engineering team supporting enterprise Identity & Access Management (IAM) applications within a large-scale security organization. This role will focus on the design, development, integration, and modernization of secure enterprise applications used internally across the organization.The ideal candidate will possess strong expertise across both frontend and backend development, with deep experience in Angular, Java, Spring Boot, REST API development, cloud-native AWS services, and secure application development practices. This individual will play a key technical leadership role within the team,...

Learn more

Senior DevOps Engineer

Added 15/09/2026

We are currently looking for a Senior DevOps Engineer to join a observability team within the energy sector. You'll play a key role in building and evolving a cloud-native observability platform used by multiple DevOps teams, helping to deliver scalable, secure and automated services across a large AWS-based environment.Additional details:Location: Amersfoort (Hybrid - 1-2 days onsite)Contract length: 6 months with option to extendTech: AWS, Kubernetes, Helm, Terraform, GitLab, ArgoCD, Prometheus, Grafana, Grafana LokiKey responsibilities include:Designing and developing observability services for internal engineering teamsEnhancing AWS-based Kubernetes platforms using Infrastructure as CodeDriving automation, GitOps adoption and operational excellenceCollaborating closely with DevOps teams...

Learn more
At least 8 characters, 1 uppercase, 1 lowercase and 1 special character or number
Your file must be a doc, docx or pdf. No larger than 5MB.