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.
Free, open-source framework for cross-platform game development
Stars
14,562Last commit
19 hours agoLicense
Unknown
Build games in C# that run on Windows, macOS, Linux, iOS, Android, and major consoles. No royalties, no subscriptions, no runtime fees.
Open Source Alternative to:
A free, open source, cross-platform video editor
Stars
15,480Last commit
2 days agoLicense
GPL-3.0
Free, open-source video editor supporting 4K resolution, hundreds of formats, and professional features like Blackmagic Design integration across Windows, Mac, and Linux.
Open Source Alternative to:
Self-hosted file sync with AI-powered organization
Stars
15,372Last commit
8 days agoLicense
Unknown
Open source file sync and sharing platform with custom properties, AI automation, collaborative editing, and enterprise-grade security for teams.
Open Source Alternative to:
Unified file management for your enterprise storage
Stars
14,822Last commit
2 days agoLicense
AGPL-3.0
Filestash is an open-source file manager that integrates with multiple storage backends, authentication systems, and offers customization options.
Open Source Alternative to:
Type shortcuts, expand to full text instantly
Stars
14,684Last commit
6 days agoLicense
GPL-3.0
Cross-platform text expander that replaces typed keywords with full snippets, templates, dates, emojis, or script output across any app.
Open Source Alternative to:
Voice-to-text that works offline, privately, on any app
Stars
Stars growing quickly over the last 30 days9,829Last commit
8 hours agoLicense
MIT
Dictation app powered by OpenAI Whisper and NVIDIA Parakeet. Runs locally on macOS, Windows, and Linux with zero data retention and 100+ language support.
Open Source Alternative to:
Collect, organize, cite, and share research in one place
Stars
15,721Last commit
8 days agoLicense
Unknown
Reference manager that captures sources from the web, organizes them with tags and collections, and generates citations in 9,000+ styles for Word, LibreOffice, and Google Docs.
Open Source Alternative to:
Self-hosted session replay with complete data control
Stars
13,040Last commit
12 hours agoLicense
AGPL-3.0
Open-source session replay and product analytics platform you can self-host for complete control over data security, privacy, and compliance.
Open Source Alternative to:
The personal finance app for everyone
Stars
Stars growing over the last 30 days10,639Last commit
22 hours agoLicense
AGPL-3.0
An all-in-one personal finance platform. Track, optimize, grow, and manage your money through every stage of life.
Open Source Alternative to:
Professional RAW photo editing and workflow management
Stars
13,309Last commit
9 hours agoLicense
GPL-3.0
Open source photography workflow application for RAW development. Non-destructive editing, professional color management, and GPU acceleration for photographers.
Open Source Alternative to:
High-performance distributed database for all workloads
Stars
10,351Last commit
1 day agoLicense
Apache-2.0
Scalable, high-availability database system supporting OLTP, OLAP, and hybrid transactional/analytical processing workloads.
Open Source Alternative to:
Graph database built for GraphRAG and multi-tenant AI apps
Stars
Stars growing quickly over the last 30 days10,499Last commit
1 day agoLicense
SSPL-1.0
Graph database using sparse matrix representation and linear algebra to deliver ultra-low latency Cypher queries, native multi-tenancy, and built-in GraphRAG support for AI applications.
Open Source Alternative to:
Lightning-fast open source search engine for big data
Stars
12,067Last commit
10 hours agoLicense
GPL-3.0
Open source search database delivering 2.83x faster performance than Elasticsearch. Features vector search, SQL interface, and full-text capabilities.
Open Source Alternative to:
On-the-fly image resizing and conversion for your own server
Stars
11,140Last commit
1 day agoLicense
Apache-2.0
Self-hosted image processing server that resizes, converts, and optimizes images on demand via URL parameters, with built-in security against common attack vectors.
Open Source Alternative to:
Professional digital painting made accessible to everyone
Stars
10,615Last commit
14 hours agoLicense
GPL-3.0
Free and open source painting program built by artists for artists. Features professional brushes, layers, animation tools, and drawing assistants for all skill levels.
Open Source Alternative to:
Serverless backend platform for modern app development
Stars
9,365Last commit
8 hours agoLicense
MIT
Fully managed backend infrastructure with built-in authentication, database, storage, and serverless functions for rapid application development.
Open Source Alternative to:
Visual development platform for modern web experiences
Stars
8,870Last commit
2 days agoLicense
MIT
Drag-and-drop interface for creating and optimizing digital experiences, with headless CMS and powerful integrations.
Open Source Alternative to:
Fast, flexible VPN replacement with zero-trust security
Stars
9,122Last commit
10 hours agoLicense
Apache-2.0
Replace your VPN with zero-trust access built on WireGuard. Fast, scalable network security with simple policies and identity provider integration.
Open Source Alternative to:
Build and play games inside a game engine that runs live
Stars
6,496Last commit
12 hours agoLicense
MIT
A game creation platform built on Valve's Source 2 engine, letting you build, share, and play games without leaving the environment.
Open Source Alternative to:
Simplify expense management for businesses of all sizes
Stars
5,071Last commit
8 hours agoLicense
MIT
Automate expense reporting, reimbursements, and corporate card management with real-time data sync and powerful integrations.
Visual app builder that integrates with your existing codebase
Stars
7,126Last commit
8 hours agoLicense
MIT
Open-source visual editor for building websites and web apps. Connect to any data source, design custom UIs, and ship production React code without leaving your stack.
Open Source Alternative to:
The tensor database for AI data
Stars
9,258Last commit
5 months agoLicense
Apache-2.0
Deep Lake is an open-source database for storing, querying and managing complex AI data like images, audio, and embeddings.
Open Source Alternative to:
Secure email, calendar and contacts with end-to-end encryption
Stars
8,039Last commit
13 hours agoLicense
GPL-3.0
Tuta offers encrypted email, calendar and contacts with quantum-resistant security, protecting your privacy without ads or tracking.
Open Source Alternative to:
Time-series database built for industrial IoT workloads
Stars
6,419Last commit
15 hours agoLicense
Apache-2.0
Apache IoTDB manages industrial IoT time-series data with high-throughput read/write, edge-cloud sync, ultra-high compression, and integrations with Hadoop, Spark, Flink, and Grafana.
Open Source Alternative to:
Enterprise monitoring for networks, apps, and infrastructure
Stars
6,498Last commit
10 hours agoLicense
AGPL-3.0
Monitors networks, servers, cloud services, IoT, and OT environments with no per-device licensing fees, available self-hosted or as a managed SaaS platform.
Open Source Alternative to:
Secure, encrypted notes for your digital life
Stars
6,681Last commit
14 hours agoLicense
AGPL-3.0
Cross-platform note-taking app with end-to-end encryption, offline access, and powerful organization features for privacy-conscious users.
Open Source Alternative to:
Professional image editing without the price tag
Stars
6,547Last commit
9 hours agoLicense
Unknown
Free, open-source image editor with professional tools for photo manipulation, digital art creation, and graphic design. Cross-platform support.
Open Source Alternative to:
Professional video editing without the price tag
Stars
Stars growing over the last 30 days5,921Last commit
15 hours agoLicense
GPL-3.0
Cross-platform non-linear video editor offering professional features for free. Edit videos on Linux, Windows, macOS, and BSD with advanced tools and effects.
Open Source Alternative to:
System-wide ad-blocking and privacy protection, no extensions needed
Stars
4,293Last commit
14 hours agoLicense
MIT
Free, open-source desktop app that blocks ads, trackers, and surveillance scripts across all browsers and apps on Windows, macOS, and Linux.
Open Source Alternative to:
Free office suite with Microsoft compatibility
Stars
Stars growing over the last 30 days4,552Last commit
8 hours agoLicense
GPL-3.0
Complete free office suite compatible with Microsoft formats (.doc, .docx, .xls, .xlsx, .ppt, .pptx). Open source alternative with regular updates.
Open Source Alternative to:
High-performance graph computing for scalable data analysis
Stars
4,628Last commit
9 hours agoLicense
Unknown
Memgraph is a scalable, in-memory graph database solution offering high-performance computing and Neo4j compatibility.
Open Source Alternative to:
One API to deploy and run agents on any model or machine
Stars
Stars growing quickly over the last 30 days3,204Last commit
9 hours agoLicense
Apache-2.0
Production-ready agent infrastructure that handles state, machines, permissions, and history so you don't have to build the platform yourself.
Open Source Alternative to:
Open-source code security engine for developers
Stars
Stars growing over the last 30 days3,224Last commit
16 hours agoLicense
LGPL-2.1
Opengrep is a community-driven fork of SemgrepCE, providing accessible static code analysis and security scanning for developers.
Open-source document editing suite for secure collaboration
Stars
3,383Last commit
12 hours agoLicense
Unknown
Powerful online document editor with Microsoft Office compatibility. Integrate into your infrastructure or use trusted hosting partners for secure team collaboration.
Open Source Alternative to:
Professional raw photo processing made free and powerful
Stars
4,245Last commit
4 days agoLicense
GPL-3.0
Free, cross-platform raw image processor with 32-bit floating point engine, advanced demosaicing algorithms, and professional-grade editing tools for photographers.
Open Source Alternative to:
Monitor, debug, and scale LLM applications with ease
Stars
Stars growing over the last 30 days2,874Last commit
2 days agoLicense
Apache-2.0
Open-source observability platform for GenAI and LLM applications. Real-time monitoring, distributed tracing, prompt management, and AI model evaluation built on OpenTelemetry.
Open Source Alternative to:
Transform any TV into professional digital signage
Stars
3,701Last commit
20 hours agoLicense
Unknown
Free open-source digital signage software that turns Raspberry Pi or old PCs into powerful display solutions. Manage images, videos, and web content easily.
Open Source Alternative to:
Fast and beautiful launcher for quick access to apps and tools
Stars
3,179Last commit
3 days agoLicense
MIT
A modern macOS launcher that provides instant access to applications, utilities, and system functions through an elegant and efficient interface.
Open Source Alternative to:
Complete IT infrastructure monitoring made simple
Stars
Stars growing over the last 30 days2,609Last commit
8 hours agoLicense
GPL-2.0
Monitor your entire IT infrastructure with 2,000+ plugins, automated discovery, and scalable architecture. Open source and enterprise solutions available.
Open Source Alternative to:
Serverless team chat over Tor, no phone number needed
Stars
2,658Last commit
5 days agoLicense
GPL-3.0
Quiet is a peer-to-peer messaging app that syncs messages directly between devices over Tor, with no central server, no phone number required, and no metadata leaks.
Open Source Alternative to:
Business rules engine with AI, visual flows, and audit trails
Stars
Stars growing over the last 30 days2,087Last commit
3 days agoLicense
MIT
Model business logic in decision tables, visual flows, and natural-language rules. Change rules without deploys, test every path, and run the same engine anywhere.
Open Source Alternative to:
Real-time stream processing made simple and affordable
Stars
2,273Last commit
12 days agoLicense
Apache-2.0
Timeplus is a lightweight, powerful, and cost-efficient stream processing platform for real-time analytics, deployed as a single binary.
Stellar Hosted – Managed Open Source software hosting in the EU: secure, compliant, fast.
Sent
CodeRabbit
Sent