Welcoming Repositories Index C Ecosystem
Top Welcoming Open-Source C Repositories
Top welcoming C repositories. Scored by real 90-day external PR merge rates, maintainer review turnaround speed, and first-time contributor success.
Updated daily • Sun, 30 Aug 2026 UTC
Tracked Repos
2,956
>100 stars verified
Avg Merge Rate
67%
90-day external PRs
Open GFIs
75
Beginner friendly issues
Welcoming Tier
23
S & A Tier maintainers
Ranked C Repositories
Showing top 50 of 2,956 ranked repositories
| Rank | Repository | Tier | Score | Merge Rate | Good First Issues |
|---|---|---|---|---|---|
| #1 | Greenbone Vulnerability Manager - The database backend for the Greenbone Community Edition | S•Elite | 74.8 | 95.4% | - |
| #2 | Programs and scripts to display "inline" in Adafruit Learning System guides | S•Elite | 73.6 | 100.0% | 1 |
| #3 | Parallel solvers for sparse linear systems featuring multigrid methods. | S•Elite | 73.2 | 97.4% | - |
| #4 | Code and examples for the Music Thing Modular Workshop Computer | S•Elite | 73.2 | 92.2% | - |
| #5 | saghul/txiki.js3,125 A tiny JavaScript runtime | B•Solid | 72.6 | 86.3% | - |
| #6 | PHP Extension interface to the Excel writing/reading library | B•Solid | 71.0 | 100.0% | - |
| #7 | AMY - A high-performance fixed-point Music synthesizer librarY | S•Elite | 70.7 | 87.5% | - |
| #8 | package compiler and linker metadata toolkit | A•Welcoming | 69.8 | 88.4% | - |
| #9 | 3D Extension Library for raylib | B•Solid | 69.0 | 100.0% | - |
| #10 | Minimal implementation of the QUIC protocol | A•Welcoming | 69.0 | 72.7% | - |
| #11 | Solo5/solo5988 A sandboxed execution environment for unikernels | B•Solid | 68.8 | 100.0% | - |
| #12 | NetHack/NetHack3,866 Official NetHack Git Repository | A•Welcoming | 67.1 | 83.3% | - |
| #13 | Tox Reference implementation for Android | B•Solid | 65.9 | 64.8% | - |
| #14 | myMPD is a standalone and mobile friendly web mpd client with a tiny footprint and advanced features. | B•Solid | 65.0 | 88.9% | - |
| #15 | termux/termux-x114,671 Termux X-server add-on. | B•Solid | 64.3 | 75.0% | - |
| #16 | An audio mixer that supports various file formats for Simple Directmedia Layer. | A•Welcoming | 63.0 | 87.5% | - |
| #17 | B•Solid | 62.1 | 100.0% | - | |
| #18 | A parser and compiler for the Gherkin language. | A•Welcoming | 62.0 | 68.4% | - |
| #19 | HandBrake/HandBrake24,020 HandBrake's development repository | B•Solid | 62.0 | 100.0% | - |
| #20 | A C client for NATS | A•Welcoming | 61.2 | 87.5% | - |
| #21 | A close-to-metal Python API for programming AMD Ryzen™ AI NPUs (AI Engines), built on an open-source MLIR-based compiler toolchain. | A•Welcoming | 60.7 | 27.3% | 28 |
| #22 | mruby/mruby5,601 Lightweight Ruby | A•Welcoming | 60.5 | 21.4% | - |
| #23 | FWGS/xash3d-fwgs2,716 Xash3D FWGS engine | A•Welcoming | 60.5 | 80.0% | - |
| #24 | A•Welcoming | 60.1 | 55.6% | - | |
| #25 | pound-emu/pound1,071 Open source emulator for the Nintedo Switch 1 and 2. Highly work in progress | B•Solid | 59.9 | 85.7% | - |
| #26 | fully OSS lightweight network video recorder system witten in C with modern js frontend | A•Welcoming | 59.6 | 30.0% | - |
| #27 | Core implementations of an open-source secure key | B•Solid | 59.6 | 88.9% | - |
| #28 | qpoint-io/qtap1,456 Qtap: An eBPF agent that captures pre-encrypted network traffic, providing rich context about egress connections and their originating processes. | A•Welcoming | 59.3 | 48.7% | - |
| #29 | Image decoding for many popular formats for Simple Directmedia Layer. | B•Solid | 58.7 | 66.7% | - |
| #30 | coolsnowwolf/lede31,589 Lean's LEDE source | B•Solid | 57.7 | 73.2% | - |
| #31 | Open source re-implementation of Tomb Raider I, Tomb Raider II and Tomb Raider III, along with additional enhancements and bugfixes | A•Welcoming | 57.7 | 20.0% | 3 |
| #32 | EdgeTX/edgetx2,396 EdgeTX is the cutting edge open source firmware for your R/C radio | A•Welcoming | 57.3 | 28.6% | - |
| #33 | rusefi/rusefi1,136 rusefi - GPL internal combustion engine control unit | A•Welcoming | 56.9 | 50.0% | 5 |
| #34 | Firedancer is Jump Crypto's Solana validator software. | A•Welcoming | 56.5 | 13.8% | - |
| #35 | Avidemux2, simple video editor | A•Welcoming | 56.1 | 100.0% | - |
| #36 | jarun/nnn21,794 n³ The unorthodox terminal file manager | B•Solid | 55.7 | 77.8% | - |
| #37 | LeechCore - Physical Memory Acquisition Library & The LeechAgent Remote Memory Acquisition Agent | B•Solid | 55.7 | 77.8% | - |
| #38 | vladelaina/Catime4,720 💌A tiny (995KB) but mighty timer in **pure C** ! — almost no memory usage!❤️🔥 Supports clock, countdown, stopwatch, Pomodoro, and fully customizable tray animations (GIFs, CPU/Mem%) 💘 Don't be shy, join here🧸: https://discord.com/invite/W3tW2gtp6g | B•Solid | 55.6 | 80.0% | - |
| #39 | Brainrot programming language interpreter | A•Welcoming | 55.2 | 14.3% | 38 |
| #40 | plpgsql_check is a linter tool (does source code static analyze) for the PostgreSQL language plpgsql (the native language for PostgreSQL store procedures). | B•Solid | 54.9 | 87.5% | - |
| #41 | Run Arm64/x86-64 Linux ELF binaries on macOS Apple Silicon | B•Solid | 54.1 | 66.7% | - |
| #42 | apache/nuttx4,002 Apache NuttX is a mature, real-time embedded operating system (RTOS) | B•Solid | 53.9 | 20.0% | - |
| #43 | A decompilation of Super Smash Bros Melee brought to you by a bunch of clever folks. | B•Solid | 53.6 | 26.3% | - |
| #44 | The classic, refined DOOM source port. For Windows PC. | B•Solid | 53.4 | 83.3% | - |
| #45 | avrdudes/avrdude1,167 AVRDUDE is a utility to program AVR microcontrollers | B•Solid | 52.9 | 100.0% | - |
| #46 | Linux Driver for USB WiFi Adapters that are based on the RTL8811CU, RTL8821CU, RTL8821CUH and RTL8731AU Chipsets - v5.12.0.4 | B•Solid | 52.7 | 33.3% | - |
| #47 | Iceman Fork - Proxmark3 | B•Solid | 52.2 | 9.1% | - |
| #48 | OpenIPC/firmware2,127 Alternative IP Camera firmware from an open community | B•Solid | 51.8 | 16.7% | - |
| #49 | Woof! is a continuation of the Boom/MBF bloodline of Doom source ports | B•Solid | 51.6 | 100.0% | - |
| #50 | Cyrus IMAP is an email, contacts and calendar server | B•Solid | 51.4 | 12.5% | - |
How to Get Your C PR Merged
1
Check C-Rank™ First: Pick projects with S or A tiers to avoid maintainer ghosts and slow review cycles.
2
Run Local Verification: Ensure test suites and formatting linters pass before opening a pull request.
3
Submit in Maintainer Windows: Check the repository report card to submit when maintainers are most active.
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Frequently Asked Questions: C Open Source
What is the most welcoming C open-source repository?
The highest-ranked C repository on GetMerged is currently greenbone/gvmd, with a C-Rank score of 74.8/100 and a 95.4% PR merge rate.
How can I find good first issues in C?
You can browse verified beginner-friendly issues in C by visiting our curated Good First Issues directory at getmerged.abhishekco.de/good-first-issue/c.
What makes a C repository ‘Super Welcoming’ on GetMerged?
A ‘Super Welcoming’ (S-Tier) C repository demonstrates an external PR merge rate above 80%, a median first response time within 24 to 48 hours, active review feedback, and clear onboarding documentation.