About me

I'm Tore Nestenius, a .NET consultant and trainer based in Göteborg, Sweden.

Sharing knowledge is a big part of who I am: building a course is how I learn a topic properly, because you don't really know something until you can explain it to others.

My focus areas

  • .NET
  • Identity
  • Web security
  • Software architecture
  • Event sourcing
  • Agentic development
  • Training
Tore Nestenius speaking on stage at NDC Copenhagen

At a glance

  • Senior .NET developer and architect, working as a consultant
  • Microsoft .NET MVP
  • Author of Dometrain video courses on ASP.NET Core authentication and OpenID Connect
  • Professional trainer for companies since 2010, teaching courses I have created myself
  • Conference and user group speaker
  • Co-organizer of the .NET Skåne user group, with more than 500 members

My Dometrain video courses

Dometrain is an online learning platform for software engineers, focused on .NET and C#. I have created these courses:

You can find all my courses on my Dometrain author page.

Getting Started: OpenID Connect, a Dometrain course by Tore Nestenius Getting Started: Authentication and Authorization in .NET, a Dometrain course by Tore Nestenius

Highlights from my journey

It started with a VIC-20

My first computer was a Commodore VIC-20. I was so hooked on programming that I took evening classes in BASIC at age 11, as the only kid in the class. I even ended up in the local newspaper, coding at a computer exhibition together with my programming teacher.

Newspaper clipping of a young Tore showing his skills at a computer exhibition

The Atari ST demo scene

With friends I co-founded the Swedish Atari ST demo group Sync, part of the demo scene. We wrote demos, programs that show off graphics, music and code in real time, and competed with other groups to get the most out of the machine. I was a coder, and everything we did was written in low-level Motorola 68000 assembly language, straight to the hardware. I also started a side-scrolling game in the style of Scramble, in 100% assembly, which I never finished.

Screenshot of the Sync STE Demo on the Atari ST
Screenshot of an unfinished side-scrolling game on the Atari ST

Audio Sculpture

I co-authored Audio Sculpture, a sound tracker for composing, editing and playing music on the Atari ST, written in 100% 68000 assembly.

Screenshot of the Audio Sculpture sound tracker on the Atari ST

My own Sega Mega Drive dev kit

I wanted to write my own games, and the ultimate challenge was to write games for game consoles. I couldn't afford an official dev kit, and there was no documentation, so I reverse-engineered the Sega Mega Drive and built my own kit, programmed from my Atari ST. I think of it as one of my biggest accomplishments. The full story is in How I built my own Sega Mega Drive hardware dev kit from scratch.

Tore's home-built Sega Mega Drive dev kit next to the console

The Programmers Heaven CD-ROMs

I turned my big collection of programming files into two CD-ROMs called Programmers Heaven, with more than 12,000 pieces of source code, tutorials and tools.

The two Programmers Heaven CD-ROMs
Cover of the first Programmers Heaven CD-ROM
Cover of Programmers Heaven 2

Programmers Heaven

The CD-ROMs became the start of the Programmers Heaven website, a developer community that reached more than 750,000 monthly visitors at its peak. I ran it full time for over eight years, and it gave me broad experience in development, operations, administration, SEO, marketing and sales.

The Programmers Heaven home page in 2008

CodePedia

When I learned about the wonderful concept of wikis, I decided to build my own wiki website for developers. CodePedia ran on my own wiki engine, and anyone could add content to it.

C# School

I published C# School, a free ebook for beginners who want to learn C# and .NET. Its 16 chapters and 338 pages take the reader from the fundamentals and object-oriented programming to real-world topics like collections, delegates, data access and threads.

Cover of the C# School ebook

Co-founding Edument

From 2010 to 2021 I was co-founder and CTO of Edument, a training and consulting company that grew to about 35 employees and five offices. It is where I got into the training business, and eventually became a trainer myself. I created and taught courses on C#, ASP.NET Core, web security, IdentityServer, architecture and Azure, for development teams in Sweden and abroad, and I still teach today.

Tore presenting a slide about infrastructure as code

cqrs.nu

In 2011 I attended one of Greg Young's early online workshops on CQRS and event sourcing, and I was hooked on these patterns. To give back to the community, we at Edument created cqrs.nu: a free guide to both patterns, with a starter kit for building and testing event-sourced systems. We also created training courses on the topic.

Co-founding .NET Skåne

In 2024 I co-founded .NET Skåne, a user group for .NET developers in southern Sweden that now has more than 500 members.

.NET Skåne logo

Open source

Two open-source projects I created and maintain:

  • CloudDebugger: a teaching and exploration tool for Azure cloud developers.
  • Coding Agent Explorer: a real-time .NET proxy and dashboard for inspecting AI coding agent API calls.

What to explore next?

If you want to know more about my work, here is where to go:

Or just say hello, through the contact page or on LinkedIn.