Charles Southey, Developer in Oxford, United Kingdom
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Charles Southey

Verified Expert  in Engineering

People Management Developer

Oxford, United Kingdom
Toptal Member Since
December 3, 2019

Charles has over 25 years of experience developing and delivering software solutions across a wide range of technologies and architectures for companies ranging from new startups to some of the world's biggest and best-known in their fields. He excels at matching business needs to the most appropriate technologies resulting in elegant and highly secure, scalable, and high-performing applications.


Sprint Enterprise Technology, Ltd.
jQuery, JavaScript, CSS, HTML, Microsoft SQL Server, ASP.NET MVC, C#
TotallySQL, Ltd.
Microsoft SQL Server, .NET, C#
Sophos Plc
Systems, C#, ASP.NET, Microsoft SQL Server




Preferred Environment

JavaScript 6, Database Design, Web Design, Graphic Design, ASP.NET Core, Next.js, React, Azure, Microsoft SQL Server, C#

The most amazing...

...system I've built is a SaaS financial services application that is now in use by over 600 companies managing the investments of over 150,000 private clients.

Work Experience

Chief Technology Officer

2011 - 2019
Sprint Enterprise Technology, Ltd.
  • Designed and built from scratch the core product for this financial services business on dedicated hosted Windows servers using ASP.NET MVC and SQL Server.
  • Developed live data integrations with 20-25 client investment platforms, data providers, and back-office systems.
  • Developed modules to aggregate and transform the data from all these disparate systems into a common data model for reporting and analysis.
  • Designed and built the main web application and a fully-brandable client portal for end investors to deliver highly configurable self-service reporting and data analysis.
  • Designed new algorithms and techniques for performing high-speed analysis over huge data sets to deliver break-through functionality.
  • Built and led the technical and operations teams throughout. Introduced a DevOps approach. The system is currently in use with over 600 financial services companies in the UK and Eire.
Technologies: jQuery, JavaScript, CSS, HTML, Microsoft SQL Server, ASP.NET MVC, C#

Founder, CTO

2010 - 2011
TotallySQL, Ltd.
  • Developed a suite of SQL Server add-ins and libraries for commercial sale.
  • Translated C++ Boost mathematical library into C# and validated all functions.
  • Created C# and SQL-hosted versions of all Excel financial and analysis functions such as IRR, XIRR, NPV, and RATE to name a few.
  • Created a rich set of C# and SQL-hosted statistical functions, models and methods including the modeling of all known statistical distributions such as Normal, and Poisson.
  • Included a Windows application for installing and managing CLR assemblies across a SQL Server farm.
Technologies: Microsoft SQL Server, .NET, C#


2005 - 2010
Sophos Plc
  • Modernized and streamlined the company's systems worldwide.
  • Introduced an online B2B eCommerce suite.
  • Created a Business Intelligence function and thereby uncovered key facts about the business to drive the reshaping of business strategy.
  • Integrated Finance, CRM and HR systems to share common data.
Technologies: Systems, C#, ASP.NET, Microsoft SQL Server

A SaaS solution for UK financial services companies. Data aggregation and transformation from 20-25 external platforms using MS SQL. ASP.NET MVC is the main application and client portal. Coded in C#, SQL, JavaScript, and jQuery.

SQL Server and C# Components

A complete suite of plug-in components (CLR modules) to extend the functionality of SQL Server. Utilities include exact analogs of all Excel financial and analytic functions, statistical functions and mathematical distributions, scientific and engineering functions, and general IO and utility functions. Includes a full C# port of the Boost C++ math library.
1987 - 1990

Master's Degree in Engineering and Computer Sciences

Cambridge University - Cambridge, UK


Microsoft Certified Solutions Architect



jQuery, jQuery UI, React, REST APIs, OpenID




ASP.NET MVC, ASP.NET Core, IdentityServer 4, OAuth 2, .NET, ASP.NET, Next.js, Knockout (Knockout.js), Flutter


RESTful Development, Database Design, Application Architecture, Agile, ITIL, DevOps


C#.NET, SQL, HTML5, JavaScript, CSS3, C#, HTML, CSS, JavaScript 6, C++, Java, REXX


Android, Windows, Web, Azure, Azure PaaS, Unix


Azure SQL, Microsoft SQL Server

Industry Expertise

Web Design


People Management, Team Leadership, Data Modeling, GUI Design, Systems, Graphic Design

Collaboration That Works

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