Open Source Projects using C
A curated collection of the 144 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.
Your personal distributed filesystem
Stars
39,286Last commit
11 days agoLicense
Apache-2.0
A cross-platform file manager that unifies your devices into a seamless, organized digital workspace.
Open Source Alternative to:
Secure authentication and access control made simple
Stars
37,487Last commit
8 hours agoLicense
Apache-2.0
Comprehensive open source identity management solution offering single sign-on, social login, and fine-grained authorization for applications and services.
Open Source Alternative to:
Open source AI coding agent for the terminal and IDE
Stars
28,673Last commit
8 hours agoLicense
Apache-2.0
Terminal-based AI coding agent that reads your codebase, edits files and runs commands, with support for Qwen, OpenAI, Anthropic, Gemini and local models.
Open Source Alternative to:
Powerful API development and testing made effortless
Stars
40,073Last commit
18 hours agoLicense
Apache-2.0
Intuitive API client for REST, GraphQL, and gRPC. Debug, test, and collaborate on APIs with ease across platforms.
Open Source Alternative to:
Fast, scalable vector database for AI applications
Stars
35,217Last commit
8 hours agoLicense
Apache-2.0
Qdrant is an open-source vector database that provides high-performance similarity search for AI and machine learning applications.
Open Source Alternative to:
Open blueprints for governed, always-on AI agents
Stars
22,822Last commit
8 hours agoLicense
Apache-2.0
Collection of open blueprints combining models, agent harnesses, and runtime controls to deploy specialized autonomous AI agents with policy-based guardrails.
Open Source Alternative to:
Blazing-fast in-memory data store for modern applications
Stars
31,816Last commit
9 hours agoLicense
Unknown
Dragonfly is a high-performance, Redis-compatible in-memory data store that delivers up to 25x more throughput and 80% lower costs than legacy solutions.
Open Source Alternative to:
Secure, private photo storage and sharing solution
Stars
29,549Last commit
11 hours agoLicense
AGPL-3.0
End-to-end encrypted cloud storage for photos and videos, offering privacy, security, and seamless cross-device syncing.
Open Source Alternative to:
Private, secure video calls with no account needed
Stars
30,131Last commit
8 hours agoLicense
Apache-2.0
Host encrypted video conferences directly in your browser, deploy on your own servers, or integrate into applications - all with this powerful open source platform.
Open Source Alternative to:
GPU-accelerated terminal built for power users
Stars
35,409Last commit
12 hours agoLicense
GPL-3.0
High-performance terminal emulator with GPU acceleration, graphics support, and advanced scripting capabilities for developers and system administrators.
Open Source Alternative to:
Private messaging with end-to-end encryption
Stars
29,520Last commit
1 day agoLicense
AGPL-3.0
Secure messaging app with state-of-the-art encryption, voice/video calls, group chats, and file sharing. No ads, trackers, or data collection.
Open Source Alternative to:
Spaced repetition flashcards that remember for you
Stars
32,248Last commit
10 hours agoLicense
Unknown
Flashcard app using spaced repetition to schedule reviews at the exact moment you're likely to forget, so you retain more with less study time.
Open Source Alternative to:
AI assistant that enhances enterprise knowledge management
Stars
23,023Last commit
17 hours agoLicense
GPL-3.0
Open-source AI solution combining RAG pipelines, workflow automation, and multi-model support for intelligent enterprise knowledge management and customer service.
Open Source Alternative to:
GPU-accelerated terminal emulator with multiplexing across all platforms
Stars
29,329Last commit
5 days agoLicense
MIT
Cross-platform terminal emulator and multiplexer with GPU acceleration, true color support, and Lua configuration. Runs on Linux, macOS, Windows, FreeBSD, and NetBSD.
Open Source Alternative to:
Local-first, Git-native personal knowledge base with AI
Stars
20,161Last commit
8 hours agoLicense
AGPL-3.0
A free, open source note-taking app built on plain Markdown files, Git version control, and direct AI model integration. No account required.
Open Source Alternative to:
Time-series database and historian for industrial data
Stars
25,169Last commit
3 days agoLicense
AGPL-3.0
High-performance time-series database with industrial data management, built-in stream analytics, and AI-driven anomaly detection for operational environments.
Open Source Alternative to:
Cross-platform, secure password manager
Stars
29,421Last commit
9 hours agoLicense
GPL-3.0
KeePassXC is an open-source password manager that securely stores and manages sensitive information across Windows, macOS, and Linux.
Open Source Alternative to:
Create 2D and 3D games without coding, powered by AI assistance
Stars
Stars growing over the last 30 days27,952Last commit
12 hours agoLicense
Unknown
Free, open-source game engine with visual event system, AI tutor, and one-click publishing to Steam, iOS, Android, and web platforms.
Open Source Alternative to:
Free, open-source image editor built for Mac compositing
Stars
Stars growing quickly over the last 30 days17,776Last commit
10 hours agoLicense
MIT
Mac-native Photoshop alternative built around compositing and post-processing workflows, with layers, masks, blend modes, filters, and background removal.
Open Source Alternative to:
Lightning-fast, typo-tolerant search engine for all
Stars
27,037Last commit
3 days agoLicense
GPL-3.0
Open-source search solution offering blazing speed, typo tolerance, and effortless scalability for developers and businesses.
Open Source Alternative to:
A native code editor for macOS
Stars
23,083Last commit
6 days agoLicense
MIT
A lightweight, natively built editor. Open source and free forever. Develop any project using any language at speeds like never before.
Open Source Alternative to:
Open-source crypto trading bot for market making
Stars
20,658Last commit
4 days agoLicense
Apache-2.0
Automate crypto trading strategies with a powerful, customizable platform. Connect to multiple exchanges and optimize your market making.
Open Source Alternative to:
Full-featured media center for your TV and beyond
Stars
21,372Last commit
13 hours agoLicense
Unknown
Plays videos, music, TV shows, photos, and games from a single interface, with live TV, PVR recording, and broad format support across devices.
Open Source Alternative to:
Self-hosted music streaming for your personal collection
Stars
24,320Last commit
13 hours agoLicense
GPL-3.0
Open source music server that streams your personal library via a web player or any Subsonic-compatible mobile app on iOS and Android.
Open Source Alternative to:
Serverless Postgres for modern applications
Stars
23,253Last commit
2 months agoLicense
Apache-2.0
Cloud-native, auto-scaling Postgres with instant branching, bottomless storage, and pay-per-use pricing
Open Source Alternative to:
Time-series database built on top of PostgreSQL
Stars
23,744Last commit
13 hours agoLicense
Unknown
PostgreSQL extension for time-series data with automatic partitioning, up to 95% columnar compression, continuous aggregates, and ~200 native SQL functions.
Open Source Alternative to:
Collaborative bookmark manager for teams and individuals
Stars
20,194Last commit
5 days agoLicense
AGPL-3.0
Open-source platform to collect, organize, and preserve webpages with powerful collaboration features
Open Source Alternative to:
Open-source workflow automation for developers
Stars
18,255Last commit
11 hours agoLicense
Unknown
Powerful, self-hosted platform for building and running workflows, scripts, and apps with code-first approach and collaborative features.
Open Source Alternative to:
Scalable open-source distributed storage system
Stars
17,157Last commit
9 hours agoLicense
Unknown
Ceph provides unified object, block, and file storage from a single cluster built on commodity hardware.
Open Source Alternative to:
Professional audio editing made simple and free
Stars
18,816Last commit
14 hours agoLicense
Unknown
Free, open-source audio editor and recorder for all platforms. Record, edit, mix and enhance audio with professional tools. Perfect for music, podcasts, and more.
Open Source Alternative to:
AI agent runtime with encrypted enclaves for your secrets
Stars
12,671Last commit
1 day agoLicense
Apache-2.0
Runs AI agents inside Trusted Execution Environments on NEAR AI Cloud, keeping credentials encrypted and invisible to the model at all times.
Open Source Alternative to:
SQLite-compatible database for scalable multi-tenant applications
Stars
17,285Last commit
7 days agoLicense
MIT
Turso provides a simple developer experience with SQLite compatibility, allowing you to build and scale multi-tenant applications with unlimited databases.
Open Source Alternative to:
Privacy-first survey and experience management platform
Stars
13,139Last commit
8 hours agoLicense
AGPL-3.0
Collect feedback across websites, apps, and emails with targeted surveys, user segmentation, and GDPR-compliant data handling. Self-host or use the cloud.
Open Source Alternative to:
Privacy-first offline maps for hiking, cycling & navigation
Stars
15,745Last commit
9 hours agoLicense
Apache-2.0
Free, open-source offline maps app with detailed trails, turn-by-turn navigation, and zero tracking. Perfect for hikers, cyclists, and travelers seeking privacy.
Open Source Alternative to:
High-performance time-series database for massive data scale
Stars
17,466Last commit
8 hours agoLicense
Apache-2.0
Open-source time-series database offering massive ingestion throughput, millisecond queries, and SQL extensions, designed for optimal performance at any hardware scale.
Open Source Alternative to:
Advanced terminal with modern features for Mac developers
Stars
18,212Last commit
21 hours agoLicense
GPL-2.0
Feature-rich terminal replacement for macOS with split panes, search, autocomplete, and extensive customization options for enhanced productivity.
Open Source Alternative to:
AI-native vector database for intuitive applications
Stars
16,908Last commit
17 hours agoLicense
BSD-3-Clause
Open-source vector database designed for building powerful, production-ready AI applications with hybrid search capabilities and flexible deployment options.
Open Source Alternative to:
Zero Trust VPN solutions for secure business networking
Stars
14,718Last commit
9 hours agoLicense
Unknown
Secure remote access VPN solutions with zero trust network access. Self-hosted and cloud-managed options for businesses of all sizes. Trusted by 20,000+ organizations.
Open Source Alternative to:
Zero-knowledge encrypted notes that sync across all devices
Stars
14,820Last commit
19 hours agoLicense
GPL-3.0
End-to-end encrypted note-taking app with zero-knowledge architecture, cross-device sync, web clipper, and a self-hostable sync server.
Open Source Alternative to:
Build full-stack apps with TypeScript and real-time sync
Stars
12,753Last commit
11 hours agoLicense
Unknown
Open-source reactive database that keeps your web and mobile apps in sync. Write everything in TypeScript with built-in auth, cron jobs, and AI integration.
Open Source Alternative to:
Remove Mac apps and all their leftover files
Stars
14,949Last commit
4 months agoLicense
Unknown
Mac app uninstaller that finds and removes associated files, orphaned leftovers, and development artifacts across macOS 13 and later.
Open Source Alternative to:
Centralize, transform, and stash your data
Stars
14,965Last commit
8 hours agoLicense
Unknown
Logstash is a free and open server-side data processing pipeline that ingests data from multiple sources, transforms it, and sends it to your desired destination.
Open Source Alternative to:
Stellar Hosted – Managed Open Source software hosting in the EU: secure, compliant, fast.
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CodeRabbit
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