C# / .NET Developer – Front Office Liquidity, Treasury & Risk Systems

Margo Group

Greater London

Hybrid

GBP 90,000 - 140,000

Full time

5 days ago

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Benefits offered by this job

Challenging projects

Front Office exposure

Career progression

Small team environment

Job summary

MARGO in London seeks a Senior C# / .NET Developer to build, modernize, and scale our front-office calculation engines. This is a hands-on, individual contributor role in a high-performance banking environment.

You will implement real-time feeds, RESTful APIs, and microservices while collaborating across Liquidity, Treasury & Risk IT. Strong C#/.NET, SQL Server, and DevOps experience are essential for delivering robust production systems.

Qualifications

Proven experience as a Senior C# .NET Developer in demanding, performance-sensitive banking environments.
Strong object-oriented design, asynchronous programming, and multithreading.
Back-end experience building event-driven services, messaging systems, and Windows Services.
MS SQL Server with Dapper expertise; lightweight ORM familiarity.
DevOps pipelines and AI developer tools (Copilot/Claude) familiarity.

Responsibilities

Design, build, and optimize high-performance back-end calculation engines using modern C# .NET.
Develop asynchronous, message-driven microservices (Rebus) and Windows Services for distributed processing.
Build and tune database objects, complex queries, and data access layers using MS SQL Server and Dapper.
Implement real-time feeds and RESTful APIs using ASP.NET Web API and SignalR.
Leverage LLMs and agentic AI workflows to accelerate testing, refactoring, and delivery.
Deliver clean, testable code adhering to SOLID principles and CI/CD pipelines.

Skills

Senior C# .NET

Performance engineering

Event-driven design

Windows Services

MS SQL Server & Dapper

RESTful APIs (ASP.NET Web API)

SignalR

DevOps familiarity

Tools

Rebus

Git

TeamCity

Jenkins

Ansible

Dapper

MS SQL Server

Job description

C# / .NET Developer – Front Office Liquidity, Treasury & Risk Systems

Join MARGO in the UK (London) – Perm & Contracting Opportunities

MARGO is a tech-native consultancy delivering high value-added IT expertise to the financial services industry. We specialise in complex software engineering environments where performance, robustness, and scalability are critical: real-time systems, distributed architectures, high-throughput engines, and complex financial calculations. Joining MARGO means working in demanding Front Office, Global Markets, and Treasury IT environments while benefiting from a human-sized structure, dedicated technical support, and tailored career development paths.

Business Context

You will join the Front Office / Treasury IT environment of a premier Tier-1 investment bank in London.

Working within the Non-Linear IT team across distributed locations, you will engineer mission-critical systems supporting Liquidity Risk, Treasury ALM, XVA, and Financial Resource Management. The platform operates in direct proximity to trading desks, Treasury, and risk managers to calculate balance-sheet funding costs and risk exposures in real time.

The team is actively executing an advanced migration toward a modern, event-driven back-end microservices architecture while supporting interactive UI tools used daily by several hundred users.

Role Overview

We are looking for a passionate Senior C# / .NET Developer to build, modernize, and scale our core front-office calculation engines.

This is a 100% hands-on Individual Contributor seat. You will write clean, high-performance back-end code and translate complex financial logic directly into production systems without business analyst or translation layers.

Key Responsibilities

Design & Engineering

Design, build, and optimize high-performance back-end calculation engines using modern C# .NET.
Develop asynchronous, message-driven microservices (using Rebus / messaging queues) and Windows Services for distributed processing.
Build and tune database objects, complex queries, and data access layers using MS SQL Server and Dapper.
Implement real-time communication feeds and RESTful APIs using ASP.NET Web API and SignalR.
Leverage LLMs and practical agentic AI workflows (Copilot, Claude) within daily engineering to accelerate testing, refactoring, and delivery.

Functional Implementation

Implement core calculation logic across at least two of the following business areas:

Liquidity Risk & Treasury: Cash-flow time-bucketing, NSFR, RNFB, LCR, or liquidity buffers.
Cash Forecasting: Forward cash projections and contractual vs. behavioral maturities.
Balance Sheet & Capital Metrics: Leverage exposure and financial resource utilization.
XVA & Pricing Adjustments: CVA, FVA, ColVA, and funding costs.
Risks & Greeks: Non-linear sensitivities (Delta, Gamma, Vega) and PnL Explain.
Financial Products: Listed or OTC derivatives.
Pre-Trade Analytics: Trade simulation, margin/funding impact checks, and booking workflows.

Delivery & Engineering Standards

Deliver clean, testable, and maintainable code adhering to SOLID principles and design patterns.
Participate in automated CI/CD pipelines using Git (Bitbucket), TeamCity, Jenkins, or Ansible.
Maintain high standards of ownership, transparency, and operational risk mitigation.

Technical Environment

Core Technologies

Languages & Frameworks: C# .NET, Windows Services, ASP.NET Web API, SignalR
Architecture & Messaging: Event-driven architecture, asynchronous message-driven systems (Rebus), Service-Oriented Architecture (SOA)
Data & Storage: MS SQL Server (performance tuning, schema design), Dapper
DevOps & CI/CD: Git, TeamCity, Jenkins, Ansible
Modern Tooling: Practical experience applying LLMs / agentic AI tools in software engineering

Valued / Nice-to-Have

Front-end web development with React, Redux, TypeScript, and HTML

Required Experience & Skills

Essential

Proven experience as a Senior C# .NET Developer in demanding, performance-sensitive banking environments.
Deep understanding of Object-Oriented design patterns, asynchronous programming, and multithreading.
Solid back-end experience building event-driven services, messaging systems, and Windows Services.
Strong MS SQL Server database expertise and experience with lightweight ORMs (Dapper).
Practical familiarity with enterprise DevOps pipelines and AI developer tools (Copilot/Claude).
A dedicated individual contributor mindset committed to daily hands-on coding.

Why Join MARGO