Hacktoberfest 2026: the issues maintainers tagged for October, open and beginner-friendly. Browse Hacktoberfest issues

Ranked by how they treat first pull requests

The most beginner-friendly C# open source projects

Projects that merge pull requests from outside contributors and answer them quickly: the two things a newcomer cannot see before sending one.

  1. C# SDK for the Hugging Face API -- inference, embeddings, and model hub

    100% of outside PRs merged Maintainers usually reply within 1 day

    1 open beginner issue 58 stars

  2. Building GenAI Apps in C#: Microsoft Extensions for AI, Templates, Microsoft Foundry & More

    100% of outside PRs merged Maintainers usually reply within 1 day

    6 open beginner issues 57 stars

  3. Content Organization for Virtual Entertainment: SFW and NSFW Media Organizer & Local Server

    92% of outside PRs merged Maintainers usually reply within 1 day

    3 open beginner issues 48 stars

  4. 4. NLog/NLog C#

    NLog - Flexible and Structured Logging for various .NET Platforms

    92% of outside PRs merged Maintainers usually reply within 1 day

    2 open beginner issues 6,547 stars

  5. API Support for your favorite torrent trackers

    89% of outside PRs merged Maintainers usually reply within 1 day

    2 open beginner issues 16,088 stars

  6. A framework for building messaging apps with .NET and C#.

    92% of outside PRs merged Maintainers usually reply within 1 day

    2 open beginner issues 2,482 stars

  7. AI-powered COBOL to Java Quarkus modernization agents using Microsoft Agent Framework. Automates legacy mainframe code modernization with intelligent agents for analysis, conversion, and dependency...

    86% of outside PRs merged Maintainers usually reply within 1 day

    4 open beginner issues 216 stars

  8. Greenshot for Windows - for more information look here:

    81% of outside PRs merged Maintainers usually reply within 1 day

    3 open beginner issues 5,123 stars

  9. 9. dotnet/docfx C#

    Static site generator for .NET API documentation.

    95% of outside PRs merged Maintainers usually reply within 1 day

    2 open beginner issues 4,448 stars

  10. SDK for the SolarWinds Orion platform, including tools, documentation, and samples in PowerShell, C#, Go, Perl, and Java.

    82% of outside PRs merged Maintainers usually reply within 1 day

    1 open beginner issue 423 stars

  11. UniGetUI: The Graphical Interface for your package managers. Could be terribly described as a package manager manager to manage your package managers

    92% of outside PRs merged Maintainers usually reply within 1 day

    4 open beginner issues 26,197 stars

  12. A community project with additional components and extensions for Aspire

    88% of outside PRs merged Maintainers usually reply within 1 day

    3 open beginner issues 628 stars

  13. 13. naudio/NAudio C#

    Audio and MIDI library for .NET

    85% of outside PRs merged Maintainers usually reply within 1 day

    1 open beginner issue 6,233 stars

  14. the subtitle editor :)

    75% of outside PRs merged Maintainers usually reply within 1 day

    5 open beginner issues 14,341 stars

  15. Documentation for ASP.NET Core

    83% of outside PRs merged Maintainers usually reply within 1 day

    14 open beginner issues 13,135 stars

  16. This repository contains set of components extending functionality of the OpenTelemetry .NET SDK. Instrumentation libraries, exporters, and other components can find their home here.

    75% of outside PRs merged Maintainers usually reply within 1 day

    2 open beginner issues 676 stars

  17. Next generation open source Altinn platform and applications.

    77% of outside PRs merged Maintainers usually reply within 1 day

    8 open beginner issues 169 stars

  18. A next-generation platform for diabetes management

    83% of outside PRs merged Maintainers usually reply within 1 day

    16 open beginner issues 132 stars

  19. VS Code Extension for Copilot Studio

    80% of outside PRs merged Maintainers usually reply within 1 day

    1 open beginner issue 112 stars

  20. 92% of outside PRs merged Maintainers usually reply within 1 day

    1 open beginner issue 34 stars

How this ranking works

Score = merge rate × reply speed. The merge rate is the share of pull requests from outside contributors (anyone who is not an owner, member or collaborator of the project, bots excluded) merged in the last 30 days, smoothed as (merged + 1) ÷ (sent + 2) so a few lucky merges do not outrank a long record. The reply speed is 1 ÷ (1 + the median number of days before a pull request gets its first reply from someone other than its author, or is merged). Bot comments do not count as replies.

Listed: projects with at least 10 outside pull requests in that window, at least one open beginner issue, at least 10 stars, a push in the last 180 days, not archived, and measured in the last 30 days.

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