# Best open source apps written in C#

> The best self-hosted apps written in C# are Jellyfin, Bitwarden and Duplicati. Jellyfin leads with 57,817 GitHub stars. Candidates: the 27 apps whose main GitHub language is C#.

## Key facts

| Fact | Value |
|---|---|
| Question | What are the best self-hosted apps written in C#? |
| Picks | 12 |
| Top pick | Jellyfin (57,817 stars) |
| Data as of | Oct 7, 2026 |
| Canonical URL | https://appsgit.com/best/open-source-apps-in-c-sharp |

## Ranked picks

- [Jellyfin](https://appsgit.com/apps/jellyfin) (57,817 stars, GPL-2.0, C#, Docker): Jellyfin has 57,817 GitHub stars, uses the GPL-2.0 license, ships a Docker image, is written in C# and had 2,025 commits in the last year; it replaces Plex and Spotify.
- [Bitwarden](https://appsgit.com/apps/bitwarden) (20,244 stars, AGPL-3.0, C#, Docker): Bitwarden has 20,244 GitHub stars, uses the AGPL-3.0 license, ships a Docker image, is written in C# and had 1,544 commits in the last year; it replaces Bitwarden and 1Password.
- [Duplicati](https://appsgit.com/apps/duplicati) (15,062 stars, MIT, C#, Docker): Duplicati has 15,062 GitHub stars, uses the MIT license, ships a Docker image, is written in C# and had 2,440 commits in the last year.
- [Sonarr](https://appsgit.com/apps/sonarr) (16,826 stars, GPL-3.0, C#, Docker): Sonarr has 16,826 GitHub stars, uses the GPL-3.0 license, ships a Docker image, is written in C# and had 610 commits in the last year.
- [Technitium DNS Server](https://appsgit.com/apps/technitium-dns-server) (10,065 stars, GPL-3.0, C#, Docker): Technitium DNS Server has 10,065 GitHub stars, uses the GPL-3.0 license, ships a Docker image, is written in C# and had 689 commits in the last year.
- [Kavita](https://appsgit.com/apps/kavita) (11,806 stars, GPL-3.0, C#, Docker): Kavita has 11,806 GitHub stars, uses the GPL-3.0 license, ships a Docker image, is written in C# and had 368 commits in the last year; it replaces Kindle and Audible.
- [Radarr](https://appsgit.com/apps/radarr) (14,506 stars, GPL-3.0, C#, Docker): Radarr has 14,506 GitHub stars, uses the GPL-3.0 license, ships a Docker image, is written in C# and had 116 commits in the last year.
- [slskd](https://appsgit.com/apps/slskd) (4,010 stars, AGPL-3.0, C#, Docker): slskd has 4,010 GitHub stars, uses the AGPL-3.0 license, ships a Docker image, is written in C# and had 1,056 commits in the last year.
- [BTCPay Server](https://appsgit.com/apps/btcpay-server) (7,786 stars, MIT, C#): BTCPay Server has 7,786 GitHub stars, uses the MIT license, is written in C# and had 707 commits in the last year.
- [Prowlarr](https://appsgit.com/apps/prowlarr) (7,330 stars, GPL-3.0, C#, Docker): Prowlarr has 7,330 GitHub stars, uses the GPL-3.0 license, ships a Docker image, is written in C# and had 147 commits in the last year.
- [Umbraco](https://appsgit.com/apps/umbraco) (5,262 stars, MIT, C#): Umbraco has 5,262 GitHub stars, uses the MIT license, is written in C# and had 2,598 commits in the last year.
- [Ombi](https://appsgit.com/apps/ombi) (4,105 stars, GPL-2.0, C#, Docker): Ombi has 4,105 GitHub stars, uses the GPL-2.0 license, ships a Docker image, is written in C# and had 351 commits in the last year.

## How this list was made

- Candidates: the 27 apps whose main GitHub language is C#.
- Base score: GitHub stars on a log scale plus commits in the last 12 months (log scale, capped at 1,000).
- Bonus points for a published Docker image, an OSI-approved open-source license and a commit in the last 90 days.
- The language is GitHub's detection for the repository; many projects also use other languages.

## FAQ

### Is Jellyfin free?

Yes. Jellyfin is open-source software released under the GPL-2.0 license, so you can self-host it at no cost. You only pay for the server it runs on, and some projects also offer an optional paid cloud plan.

### Can I self-host these apps with Docker?

Yes, 10 of the 12 picks. Jellyfin, Bitwarden and Duplicati publish Docker images, so you can run them on a VPS or home server with Docker Compose. The others install from their own packages or source; follow each project's install guide.

### Are all of these apps open source?

All 12 apps on this list are open source. You can self-host and modify each one under its license.

### Which of these apps is the most actively developed?

Umbraco, with 2,598 commits in the last 12 months and a latest release, release-18.2.1, from October 2026. Activity is a good sign that bugs and security issues get fixed.

## Related questions

- [What are the best self-hosted apps written in Ruby?](https://appsgit.com/best/open-source-apps-in-ruby)
- [What are the best MIT-licensed self-hosted apps?](https://appsgit.com/best/mit-licensed-self-hosted-apps)
- [What are the best AGPL-licensed self-hosted apps?](https://appsgit.com/best/agpl-self-hosted-apps)
- [What are the best self-hosted apps for beginners?](https://appsgit.com/best/docker-self-hosted-apps-for-beginners)
- [What are the best source-available self-hosted apps?](https://appsgit.com/best/source-available-apps)
- [What are the trending GitHub projects right now?](https://appsgit.com/best/trending-github-projects)
- [What is the best open source PDF editor you can self-host?](https://appsgit.com/best/open-source-pdf-tools)
- [What is the best open source YouTube downloader?](https://appsgit.com/best/youtube-downloaders)

## See also

- [Open-source alternatives to Plex](https://appsgit.com/alternatives/plex)
- [Open-source alternatives to Spotify](https://appsgit.com/alternatives/spotify)
- [Open-source alternatives to Netflix](https://appsgit.com/alternatives/netflix)
- [Open-source alternatives to Audible](https://appsgit.com/alternatives/audible)
- [Open-source alternatives to Bitwarden](https://appsgit.com/alternatives/bitwarden)
- [Open-source alternatives to 1Password](https://appsgit.com/alternatives/1password)
- [Navidrome vs Jellyfin](https://appsgit.com/compare/navidrome-music-server-vs-jellyfin)
- [Vaultwarden vs Bitwarden](https://appsgit.com/compare/vaultwarden-vs-bitwarden)
- [How to self-host Jellyfin with Docker Compose](https://appsgit.com/guides/jellyfin)

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Canonical page: https://appsgit.com/best/open-source-apps-in-c-sharp
Source: appsgit (https://appsgit.com), the app store for github. Data from the GitHub API, refreshed nightly.
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