Mark Heydon
Solo C#/.NET developer
Practical tools for Microsoft 365 Business and small-business ops, built with AI in the loop so more actually ships.
Welcome to my profile site!
About Me
I’m a software engineer, self-taught from an early age, who later formalised that with a Software Engineering degree from the Open University. Decades of professional development and commercial experience.
I build practical tools for smaller businesses’ day-to-day operations, with a particular focus on Microsoft 365 Business technologies. I’m passionate about open source work: design it, ship it, keep it maintained, because the problems are real. I maintain a fleet of GitHub repositories: importing work into Microsoft Planner, talking to FreeAgent from .NET, logging WordPress CLI jobs properly. Sponsorship and paid work help fund that, although I’m not pretending open source alone pays the bills. As a solo developer I use AI coding tools openly: not instead of knowing how to build, but so more of the right work actually ships. These days that’s mainly C#/.NET and PowerShell, with WordPress still in the mix. I keep current with things like .NET Aspire.
Tools and platforms I use to build and maintain that work:- C#
- .NET
- PowerShell
- Blazor
- Microsoft Graph
- Azure
- Bicep
- PHP
- WordPress
- GitHub
- Hugo
- Aspire
- Dataverse
Experience
Software Engineer
-
MHCG LTD
Apr 2009 - Present
I build practical tools for smaller businesses’ day-to-day operations, with a focus on Microsoft 365 Business as a domain to build in. Applications, automation, and integrations (Power Platform and Dataverse where they fit), alongside C#/.NET and related work.
- Design and build business applications and integrations around Microsoft 365 Business
- Automate operations with Power Platform, Dataverse, and custom .NET where needed
- Maintain public open-source tools alongside that work (GitHub)
Development Manager
-
Ashtead Plant Hire Co Ltd
Sep 2002 - Apr 2009
Responsible for a small team of developers coding in classic ASP and ASP.NET/C#, working primarily on the company-wide intranet. Integration with a legacy Unix-based POS system was a major part of the role.
Education
My Projects
C#
Blazor
Aspire
SoloDevBoard
A single pane of glass for solo developers managing GitHub work across many repositories.
PHP
Monolog
WP-CLI
Monolog WP-CLI Handler
A Monolog handler that routes log output through WP-CLI, upgraded to Monolog 3 this year.
PHP
PHPUnit
Playwright
National Lottery Generator App
A personal project that generates UK lottery numbers for fun, now a small vanilla PHP app, no …
C#
Blazor
Aspire
MeatyTimes
A roast calculator that turns meat type, weight, and doneness into cooking times and a serve-at …
C#
Blazor
Microsoft Graph
Import To Planner
A guided CSV-to-Microsoft Planner import, with validation, preview, and an explicit confirm step.
Azure
Bicep
Occasional Use Azure Virtual Desktop (AVD) Bicep
A Bicep-driven Azure Virtual Desktop deployment designed for quick, occasional use.
C#
.NET
OAuth
FreeAgent .NET Client
An open-source .NET client for the FreeAgent API with OAuth 2.0, retries, and pagination.
Hugo
GitHub Pages
AI
The Teachings of Monkey Site
TV show fansite showing how AI and open source tools might be used in a fun, collaborative way.
C#
Dataverse
Blazor
Hosted Sites Billing App
Domain model and billing integration for hosted WordPress sites.
Get in Touch
If you want to talk about a project or an open-source tool, email me.