Dennis Doomen
@dennisdoomen.com
Microsoft MVP | Coding Architect | .NET Tech Lead | .NET & C# | TypeScript | Fluent Assertions Author | International Speaker | Occasional Trainer | React & VueJS | Event Sourcing Veteran | DDD Designer | TDD Practitioner | Clean Code Writer
February 12, 2026 at 2:57 PM
Although version 8.9 of #fluentassertions is on the way, we couldn't help ourselves and also ship a tiny bugfix for version 7. See github.com/fluentassert...
February 10, 2026 at 1:08 PM
Although version 8.9 of #fluentassertions is on the way, we couldn't help ourselves and also ship a tiny bugfix for version 7. See github.com/fluentassert...
Oh dear. GitHub is down...
February 9, 2026 at 4:36 PM
Oh dear. GitHub is down...
Last night, I've released version 1.2 of Mockly. It improves the failure message that it produces if the actual HTTP request did not match any of the mocked calls. It also includes information about the actual request body. Check out the release notes at github.com/dennisdoomen...
February 9, 2026 at 1:45 PM
Last night, I've released version 1.2 of Mockly. It improves the failure message that it produces if the actual HTTP request did not match any of the mocked calls. It also includes information about the actual request body. Check out the release notes at github.com/dennisdoomen...
Check it out at github.com/dennisdoomen...
GitHub - dennisdoomen/reflectify: Simple source only reflection library with default interface property support
Simple source only reflection library with default interface property support - dennisdoomen/reflectify
github.com
February 3, 2026 at 4:06 PM
Check it out at github.com/dennisdoomen...
I've shipped a new version of Reflectify, a .NET library full of convenient extension methods to make working with Reflection a lot easier. And what's even cooler, this package comes as a source-only NuGet package. If you use it, you don't get a binary dependency on another DLL.
February 3, 2026 at 4:06 PM
I've shipped a new version of Reflectify, a .NET library full of convenient extension methods to make working with Reflection a lot easier. And what's even cooler, this package comes as a source-only NuGet package. If you use it, you don't get a binary dependency on another DLL.
Another quality-of-life feature in Fluent Assertions 8 is the way a construct like...
action.Should().Throw<SomeException>().WithMessage("*some wildcard*")
...reports the difference between the actual exception message and the expected one.
action.Should().Throw<SomeException>().WithMessage("*some wildcard*")
...reports the difference between the actual exception message and the expected one.
January 28, 2026 at 4:33 PM
Another quality-of-life feature in Fluent Assertions 8 is the way a construct like...
action.Should().Throw<SomeException>().WithMessage("*some wildcard*")
...reports the difference between the actual exception message and the expected one.
action.Should().Throw<SomeException>().WithMessage("*some wildcard*")
...reports the difference between the actual exception message and the expected one.
Because of the negative reviews I was hesitant about "Avatar: Fire and Ash". But because of a lazy Sunday, I took my son to our local IMAX 3D HFR cinema after all. I'm so happy I did. I loved the visuals, I was genuinely moved by the story, and I was blown away by the music. Go see it!
January 26, 2026 at 1:28 PM
Because of the negative reviews I was hesitant about "Avatar: Fire and Ash". But because of a lazy Sunday, I took my son to our local IMAX 3D HFR cinema after all. I'm so happy I did. I loved the visuals, I was genuinely moved by the story, and I was blown away by the music. Go see it!
One of the small quality-of-life features in Fluent Assertions 8 is that it will provide more context when two strings differ in a construct like "subject.Should().Be(expected)".
Note that "BeEquivalentTo" will only do that when the IncludingFullStringsInDifference option is used.
Note that "BeEquivalentTo" will only do that when the IncludingFullStringsInDifference option is used.
January 26, 2026 at 12:45 PM
One of the small quality-of-life features in Fluent Assertions 8 is that it will provide more context when two strings differ in a construct like "subject.Should().Be(expected)".
Note that "BeEquivalentTo" will only do that when the IncludingFullStringsInDifference option is used.
Note that "BeEquivalentTo" will only do that when the IncludingFullStringsInDifference option is used.
Soon, at a conference or event near you...
January 21, 2026 at 3:53 PM
Soon, at a conference or event near you...
Although #Mockly's fluent API provides a lot of power to build complicated HTTP mocks, sometimes you just want to provide a full URL with wildcards. Well, that's supported too.
Check out the documentation at github.com/dennisdoomen...
Check out the documentation at github.com/dennisdoomen...
January 20, 2026 at 12:20 PM
Although #Mockly's fluent API provides a lot of power to build complicated HTTP mocks, sometimes you just want to provide a full URL with wildcards. Well, that's supported too.
Check out the documentation at github.com/dennisdoomen...
Check out the documentation at github.com/dennisdoomen...
January 12, 2026 at 7:27 PM
...unit tests where you need multiple mocks (even though I strongly recommend against that), this becomes a burden.
#Mockly was designed for that and will provide as much information as possible. Not only in the failure message (as you can see in the picture), but also by providing extensive...
#Mockly was designed for that and will provide as much information as possible. Not only in the failure message (as you can see in the picture), but also by providing extensive...
January 12, 2026 at 7:27 PM
...unit tests where you need multiple mocks (even though I strongly recommend against that), this becomes a burden.
#Mockly was designed for that and will provide as much information as possible. Not only in the failure message (as you can see in the picture), but also by providing extensive...
#Mockly was designed for that and will provide as much information as possible. Not only in the failure message (as you can see in the picture), but also by providing extensive...
One of the most annoying aspects of a lot of HTTP mocking libraries in .NET is that it takes way too much time to figure out why the mock wasn't invoked correctly. E.g. Did I use the wrong path? The wrong query maybe? Did I make a mistake in the order? Especially with the more complicated...
January 12, 2026 at 7:27 PM
One of the most annoying aspects of a lot of HTTP mocking libraries in .NET is that it takes way too much time to figure out why the mock wasn't invoked correctly. E.g. Did I use the wrong path? The wrong query maybe? Did I make a mistake in the order? Especially with the more complicated...
Looking forward to what 2026 will bring for me in terms of conferences. But I can already confirm you will find me in Redmond, Stockholm, Athens, Krakow and Mannheim.
January 7, 2026 at 7:35 AM
Looking forward to what 2026 will bring for me in terms of conferences. But I can already confirm you will find me in Redmond, Stockholm, Athens, Krakow and Mannheim.
🔧598 contributions on GitHub with the longest streak being 12 days
⬆️483 commits pushed 🛎️ 51 hotel nights
🔗 233K LinkedIn impressions
✈️18 Flights
💴5th year as the treasurer of my kids' handball club 🛳️ 48 GitHub releases (minor and major)
🛳️ 48 GitHub releases (minor and major)
⬆️483 commits pushed 🛎️ 51 hotel nights
🔗 233K LinkedIn impressions
✈️18 Flights
💴5th year as the treasurer of my kids' handball club 🛳️ 48 GitHub releases (minor and major)
🛳️ 48 GitHub releases (minor and major)
January 5, 2026 at 3:30 PM
🔧598 contributions on GitHub with the longest streak being 12 days
⬆️483 commits pushed 🛎️ 51 hotel nights
🔗 233K LinkedIn impressions
✈️18 Flights
💴5th year as the treasurer of my kids' handball club 🛳️ 48 GitHub releases (minor and major)
🛳️ 48 GitHub releases (minor and major)
⬆️483 commits pushed 🛎️ 51 hotel nights
🔗 233K LinkedIn impressions
✈️18 Flights
💴5th year as the treasurer of my kids' handball club 🛳️ 48 GitHub releases (minor and major)
🛳️ 48 GitHub releases (minor and major)
🎤17 public talks of which 12 outside the Netherlands 👥3 workshops
🎙️1 podcast
🧑🏫1 lecture at a university
🏠Visited 8 countries
🥳19 years at Aviva Solutions
🏆3rd year as a Microsoft Most Valuable Professional (MVP)...
🎙️1 podcast
🧑🏫1 lecture at a university
🏠Visited 8 countries
🥳19 years at Aviva Solutions
🏆3rd year as a Microsoft Most Valuable Professional (MVP)...
January 5, 2026 at 3:30 PM
🎤17 public talks of which 12 outside the Netherlands 👥3 workshops
🎙️1 podcast
🧑🏫1 lecture at a university
🏠Visited 8 countries
🥳19 years at Aviva Solutions
🏆3rd year as a Microsoft Most Valuable Professional (MVP)...
🎙️1 podcast
🧑🏫1 lecture at a university
🏠Visited 8 countries
🥳19 years at Aviva Solutions
🏆3rd year as a Microsoft Most Valuable Professional (MVP)...
I know it's cheesy at best, but I couldn't resist myself. So this is what 2025 looked like for me.
⏬ 150 million downloads of my projects
💰1 open-source project got commercial
⭐4 new open-source projects with 24K downloads in total...
⏬ 150 million downloads of my projects
💰1 open-source project got commercial
⭐4 new open-source projects with 24K downloads in total...
January 5, 2026 at 3:30 PM
I know it's cheesy at best, but I couldn't resist myself. So this is what 2025 looked like for me.
⏬ 150 million downloads of my projects
💰1 open-source project got commercial
⭐4 new open-source projects with 24K downloads in total...
⏬ 150 million downloads of my projects
💰1 open-source project got commercial
⭐4 new open-source projects with 24K downloads in total...
They all started because I needed them personally and use everything I've learned from 3 decades of software development and 15 years of open-source development.
Check them out at github.com/dennisdoomen/
Check them out at github.com/dennisdoomen/
dennisdoomen - Overview
Microsoft MVP | .NET Software Architect | Tech Lead | Senior Dev | Fluent Assertions | Speaker | Trainer | C# | .NET | Event Sourcing - dennisdoomen
github.com
December 30, 2025 at 3:19 PM
They all started because I needed them personally and use everything I've learned from 3 decades of software development and 15 years of open-source development.
Check them out at github.com/dennisdoomen/
Check them out at github.com/dennisdoomen/
🔧.NET Library Starter Kit; A battle-tested starter kit for building open-source and internal NuGet libraries using "dotnet new", born from half a billion downloads (cont'd)
December 30, 2025 at 3:19 PM
🔧.NET Library Starter Kit; A battle-tested starter kit for building open-source and internal NuGet libraries using "dotnet new", born from half a billion downloads (cont'd)
📃PackageGuard; dependency scanner to ensure only certain NuGet and NPM packages are used
🛜Mockly; fluent HTTP mocking for .NET like it should have been done (cont'd)
🛜Mockly; fluent HTTP mocking for .NET like it should have been done (cont'd)
December 30, 2025 at 3:19 PM
📃PackageGuard; dependency scanner to ensure only certain NuGet and NPM packages are used
🛜Mockly; fluent HTTP mocking for .NET like it should have been done (cont'd)
🛜Mockly; fluent HTTP mocking for .NET like it should have been done (cont'd)
📂Pathy; fluently building and using file and directory paths without binary dependencies
🔍Reflectify; simple source only reflection library with default interface property support (cont'd)
🔍Reflectify; simple source only reflection library with default interface property support (cont'd)
December 30, 2025 at 3:19 PM
📂Pathy; fluently building and using file and directory paths without binary dependencies
🔍Reflectify; simple source only reflection library with default interface property support (cont'd)
🔍Reflectify; simple source only reflection library with default interface property support (cont'd)
I don't know why, but somehow 2025 has been the year were I suddenly felt energized to create a whole bunch of new open-source projects. In fact, I started 5 (!) new projects in the last 15 months, next to continuing the development of FluentAssertions (and we're at 8.8 now). (cont'd)
December 30, 2025 at 3:19 PM
I don't know why, but somehow 2025 has been the year were I suddenly felt energized to create a whole bunch of new open-source projects. In fact, I started 5 (!) new projects in the last 15 months, next to continuing the development of FluentAssertions (and we're at 8.8 now). (cont'd)
And if you're wondering why Mockly is the next best thing for HTTP mocking in .NET land, check out the docs at github.com/dennisdoomen...
December 24, 2025 at 6:20 AM
And if you're wondering why Mockly is the next best thing for HTTP mocking in .NET land, check out the docs at github.com/dennisdoomen...