Top Open Source Projects using C

A curated collection of the 92 best open source software using C. Find the most popular and trending open source projects to learn from, contribute to, or use in your own projects.

GIMP

The GNU Image Manipulation Program, a free image editor whose source tree is published here as the unstable 3.3 development series.

Alternative to:

Adobe Photoshop

Professional image editing without the price tag

Stars
6,397
Forks
887
Last commit
5 days ago

Standard Notes

An end-to-end encrypted notes app that syncs across desktop, mobile and web for people who want their notes unreadable to the host.

Alternative to:

Notion

Secure, encrypted notes for your digital life

Stars
6,622

Memgraph

In-memory graph database written in C and C++ that speaks Cypher, built for real-time analytics and AI retrieval over connected data.

Alternative to:

Amazon Neptune

High-performance graph computing for scalable data analysis

Stars

Zen

System-wide ad and tracker blocker for Windows, macOS and Linux that filters traffic from every application, not just the browser.

Alternative to:

AdGuard

System-wide ad-blocking and privacy protection, no extensions needed

Stars
4,219

RawTherapee

Cross-platform raw photo processing program for enthusiasts and semi-professionals who want detailed control over demosaicing and development.

Alternative to:

Adobe Lightroom

Professional raw photo processing made free and powerful

Stars

Anthias

Digital signage software for Raspberry Pi, PCs and generic ARM boards, for anyone turning an ordinary screen into a managed display.

Alternative to:

OptiSigns

Transform any TV into professional digital signage

Stars
3,660

Shelf

Asset management for teams tracking equipment, tools, vehicles and inventory across locations, using printed QR tags and booking calendars.

Alternative to:

Asset Panda

Track gear, bookings, and inventory without spreadsheets

Stars
3,004

Sol

A macOS app launcher for people who want search, window management and clipboard history in one native, keyboard-driven tool.

Alternative to:

Alfred

Fast and beautiful launcher for quick access to apps and tools

Stars
3,097

Rakazo

Self-hosted platform for persistent AI teammates with their own memory, computers and tools, reachable from web, desktop and mobile clients.

Alternative to:

Lindy

Self-hosted AI agents that do real work on your machine

Quiet

Serverless team chat for privacy minded groups, syncing messages directly between member devices over Tor with no phone number required.

Alternative to:

Slack

Serverless team chat over Tor, no phone number needed

Stars
2,646

Synara

Desktop workspace for running coding agents such as Claude Code, Codex and Cursor side by side on local projects.

Alternative to:

Cursor

Code with Claude, Codex, Gemini, and more in one workspace

Nagios

Host, service, and network monitoring written in C, with checks supplied as external plugin programs and an optional CGI web interface.

Alternative to:

Datadog

Complete infrastructure monitoring with 25+ years of expertise

Stars
2,041

Apache Cloudberry

A massively parallel PostgreSQL-based data warehouse from the original Greenplum developers, built for large-scale analytics and AI workloads.

Alternative to:

Amazon Redshift

Unlock Data's Potential with Open Source Power

Stars

Amical

A local-first dictation app that transcribes speech with Whisper on your own machine and formats the result for whichever app you are using.

Alternative to:

Aqua Voice

Type 10x faster with AI-powered voice dictation

Stars
1,523

Beaver Notes

A local-first markdown notes app for desktop and mobile, with no account wall, no editor telemetry, and sync you choose yourself.

Alternative to:

Evernote

Local-first notes app with no cloud, no AI, no tracking

Stars
1,337

Browser Operator

A desktop AI browser that runs multi-agent research, comparison and automation locally, using whichever model provider you configure yourself.

Alternative to:

Dia

Open-source AI browser for intelligent web automation

Stars

CoMaps

Community-run offline maps app built on OpenStreetMap data, for hikers, cyclists and drivers who want navigation without tracking or ads.

Alternative to:

Apple Maps

Navigate anywhere offline with complete privacy

Stars
535

Stars
105

Justnote

A privacy-focused note-taking app with end-to-end encryption on Stacks, for people who want to own both their notes and their account.

Alternative to:

Evernote

Privacy-focused note-taking made simple and fast

Stars
67

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Top Open Source Projects using C

A curated collection of the 92 best open source software using C. Find the most popular and trending open source projects to learn from, contribute to, or use in your own projects.

GIMP

Standard Notes

Memgraph

Zen

RawTherapee

Anthias

Shelf

Sol

Rakazo

Quiet

Synara

Nagios

Apache Cloudberry

Amical

Beaver Notes

Browser Operator

CoMaps

Jarvis

Prismical

Brace.to

Justnote

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