InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now. Learn more →
Top 23 C# Open-Source Projects
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Project mention: Jellyfin unauthenticated endpoints can leak data about your collection and more | news.ycombinator.com | 2025-04-23
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InfluxDB
InfluxDB – Built for High-Performance Time Series Workloads. InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now.
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Project mention: File Pilot: A file explorer built for speed with a modern, robust interface | news.ycombinator.com | 2025-02-18
Another file explorer option is Files [0], that looks a lot more like the built in Explorer in Windows but with some additional features.
[0] https://files.community/
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ShareX
ShareX is a free and open source program that lets you capture or record any area of your screen and share it with a single press of a key. It also allows uploading images, text or other types of files to many supported destinations you can choose from.
I made sure to document every step of the way via screenshots to ensure I could test enabling and disabling certain features. The screenshot tool I use on Windows is called, ShareX, and I find it extremely useful with regards to pointing out certain elements in an image.
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> Won't fix: https://github.com/microsoft/calculator/issues/148
I don't see how one can expect them to take a report worded this way seriously. Perhaps if they actually reported the crash without the tantrum the team would fix it.
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Avalonia
Develop Desktop, Embedded, Mobile and WebAssembly apps with C# and XAML. The most popular .NET UI client technology
Check out https://avaloniaui.net as well. It's basically a cross-platform reimplementation of WPF. It's not quite as simple as C#+WinForms or Lazarus+LCL because you don't get drag-and-drop UI designer, and you need to write markup by hand (albeit with live preview). But unlike HTML, it's actually designed for desktop UI apps from the get go, so it's much easier to write for anything non-trivial. And you can still write "quick and dirty" GUI code by directly connecting event handlers to buttons and updating values etc in it, ignoring data bindings and other more advanced facilities.
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WaveFunctionCollapse
Bitmap & tilemap generation from a single example with the help of ideas from quantum mechanics
Project mention: Generating an infinite world with the Wave Function Collapse algorithm | news.ycombinator.com | 2025-01-18https://github.com/mxgmn/WaveFunctionCollapse
As for global repetition, the original repo did have this to say, that selecting tiles is important.
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SaaSHub
SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives
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Project mention: DevOps in 2025: the future is automated, git-ified, and kinda scary but fun. | dev.to | 2025-05-09
Pulumi infra-as-code but with real programming languages
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awesome-dotnet-core
:honeybee: A collection of awesome .NET core libraries, tools, frameworks and software
I have a confession to make. I love writing automated tests. That's why I've created awesome-dotnet-testing – a curated list of awesome .NET libraries and tools that help ensure code quality through automated testing. While my source of inspiration was awesome-dotnet-core, sadly that massive project doesn't seem to be actively maintained anymore, with some notable projects missing, and some obsolete. This is why I have started a new categorised list with a focus solely on testing, and I'm going to keep it up to date and comprehensive. I've even learned a few new things along the way, even though I've been working with testing on .NET for a long time. So I would be happy if it helps someone.
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On GitHub, there is a special type of repository called "awesome" — these are collections of links and resources compiled on specific topics, for example, awesome-dotnet. My goal was to promote my library in each of these repositories. Although this was not an easy task — a library with 10-15 stars on GitHub does not attract much interest — I still managed to get into several of them. This significantly increased user traffic and drew attention to my project.
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Roslyn
The Roslyn .NET compiler provides C# and Visual Basic languages with rich code analysis APIs.
Project mention: OpenVSX, which VSCode forks rely on for extensions, down for 24 hours | news.ycombinator.com | 2025-04-24 -
You can find the road map here.
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ANTLR
ANTLR (ANother Tool for Language Recognition) is a powerful parser generator for reading, processing, executing, or translating structured text or binary files.
We've chosen ANTLR v4. The tool is also written in Java, which makes it really easy to use. Over many years of development, it has started to fare very well.
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CleanArchitecture
Clean Architecture Solution Template: A proven Clean Architecture Template for ASP.NET Core 9 (by ardalis)
Looking at this, it has similar aspects as ASP.NET Core, and the same flaws as the Controller per class design used. Methods such as "create", "show" and "store" do not share a state, they shouldn't share a class either.
However, you can rectify this, by just not trying to share a class with any of those. In .NET Steve Smith, aka Ardalis shows how to do this with his Clean architecture idea [1], Idea is to make a class for each endpoint. This also makes it easier for "Update" classes to share functionality with other "Update" classes and so on.
[1]: https://github.com/ardalis/CleanArchitecture/tree/main/sampl...
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Bitwarden - Open-source password manager.
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lively
Free and open-source software that allows users to set animated desktop wallpapers and screensavers powered by WinUI 3.
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amplication
Amplication brings order to the chaos of large-scale software development by creating Golden Paths for developers - streamlined workflows that drive consistency, enable high-quality code practices, simplify onboarding, and accelerate standardized delivery across teams.
Project mention: Top 15 Open-Source Low-Code Projects with the Most GitHub Stars | dev.to | 2024-07-18GitHub https://github.com/amplication/amplication GitHub Stars 14.8k Most Recent Update on GitHub Within one day Open Source License Apache 2.0 Number of Active Contributors This Year 15 Acceptance of External PRs Yes Official Website https://amplication.com/ Documentation https://docs.amplication.com/
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OpenRA
Open Source real-time strategy game engine for early Westwood games such as Command & Conquer: Red Alert written in C# using SDL and OpenGL. Runs on Windows, Linux, *BSD and Mac OS X.
OpenRA did it better :D
If you haven't seen it yet https://www.openra.net/ is worth your time.
https://github.com/OpenRA/OpenRA
I have many fond memories of playing openra as "LAN" game on the "gaming weekends" from a few FOSS groups I've been in. Can't recommend "saturday gaming" enough to anyone involved in any foss community.
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guiadevbrasil
Um guia extenso de informações com um vasto conteúdo de várias áreas para ajudar, agregar conhecimento e retirar dúvidas, nesse guia você encontrará tudo que necessário para qualquer carreira relacionada a tecnologia.
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ABP
Open-source web application framework for ASP.NET Core! Offers an opinionated architecture to build enterprise software solutions with best practices on top of the .NET. Provides the fundamental infrastructure, cross-cutting-concern implementations, startup templates, application modules, UI themes, tooling and documentation.
Project mention: Open-source web application framework for ASP.NET Core | news.ycombinator.com | 2024-09-28What is going on with all the .zip files in git? https://github.com/abpframework/abp/blob/8.3.1/source-code/V...
Bonus points for having them twice: https://github.com/abpframework/abp/blob/8.3.1/studio/source...
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2. Deserializing JSON into objects I knew for this project I'd have to deserialize GeoJSON into objects to work with them effectively in the app. Building this beast of a class felt quite daunting for being brand new to Dart and also for what was quite a complex GeoJSON file. However, I found an open source library called quicktype that generates strongly-typed models and serializers from JSON type scripts to a number of languages, including Dart. All you have to do is put in the JSON you want decoded, and it will return a prebuilt class that you can then use in your project. Quicktype have a handy website front end (https://app.quicktype.io/) for this - it worked first time and I was so grateful not to have to build this myself!
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SaaSHub
SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives
NOTE:
The open source projects on this list are ordered by number of github stars.
The number of mentions indicates repo mentiontions in the last 12 Months or
since we started tracking (Dec 2020).
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A note from our sponsor - InfluxDB
www.influxdata.com | 15 May 2025
Index
What are some of the best open-source C# projects? This list will help you:
| # | Project | Stars |
|---|---|---|
| 1 | Jellyfin | 39,416 |
| 2 | Files | 37,015 |
| 3 | ShareX | 32,273 |
| 4 | calculator | 30,304 |
| 5 | DevToys | 28,815 |
| 6 | Avalonia | 27,583 |
| 7 | WaveFunctionCollapse | 24,009 |
| 8 | Pulumi | 22,985 |
| 9 | SteamTools | 22,022 |
| 10 | awesome-dotnet-core | 20,445 |
| 11 | awesome-dotnet | 20,122 |
| 12 | Roslyn | 19,531 |
| 13 | AspNetCore-Developer-Roadmap | 19,137 |
| 14 | ANTLR | 17,925 |
| 15 | PEASS-ng | 17,486 |
| 16 | CleanArchitecture | 17,025 |
| 17 | Bitwarden | 16,504 |
| 18 | lively | 16,299 |
| 19 | amplication | 15,659 |
| 20 | OpenRA | 15,559 |
| 21 | guiadevbrasil | 14,928 |
| 22 | ABP | 13,475 |
| 23 | quicktype | 12,961 |
Sponsored
InfluxDB – Built for High-Performance Time Series Workloads
InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now.
www.influxdata.com