Top Open Source Projects using C++
A curated collection of the 79 best free and open-source projects built using C++. Discover popular repositories, architecture patterns, and trending software in 2026.
Zen Browser
MPL-2.0A Firefox-based browser offering enhanced privacy, split views, and extensive customization options for a personalized browsing experience.
YunoHost
AGPL-3.0Install and maintain your own server with minimal technical knowledge. Host websites, email, cloud storage, social networks, and more for complete digital independence.
Waterfox
NOASSERTIONFirefox-based browser with built-in ad blocking, oblivious DNS, zero telemetry, tree-style tabs, and no AI features sending your data anywhere.
TimescaleDb
NOASSERTIONPostgreSQL extension for time-series data with automatic partitioning, up to 95% columnar compression, continuous aggregates, and ~200 native SQL functions.
Shotcut
GPL-3.0Free, open-source video editor supporting 4K resolution, hundreds of formats, and professional features like Blackmagic Design integration across Windows, Mac, and Linux.
GPT4All
MITGPT4All runs open-source language models locally on Windows, macOS, and Linux with no cloud dependency, keeping your data on your machine.
NetData
GPL-3.0Powerful, efficient, and user-friendly monitoring solution for servers, containers, and applications with instant insights and alerts.
Nagios
GPL-2.0Free open source IT monitoring solution for servers, networks, and applications. Trusted by 1M+ users worldwide with powerful alerting and enterprise-grade features.
LibreOffice
GPL-3.0Complete free office suite compatible with Microsoft formats (.doc, .docx, .xls, .xlsx, .ppt, .pptx). Open source alternative with regular updates.
GIMP
NOASSERTIONFree, open-source image editor with professional tools for photo manipulation, digital art creation, and graphic design. Cross-platform support.
Darktable
GPL-3.0Open source photography workflow application for RAW development. Non-destructive editing, professional color management, and GPU acceleration for photographers.
Audacity
NOASSERTIONFree, open-source audio editor and recorder for all platforms. Record, edit, mix and enhance audio with professional tools. Perfect for music, podcasts, and more.
Activeloop
Apache-2.0Continual Learning Infrastructure for AI Agents
Voiden
Apache-2.0Offline-first API workspace that unifies specs, docs, tests, and mocks in programmable Markdown blocks. Version control everything in plain text files.
Valour
AGPL-3.0Open-source communication platform with multi-window chat, economy systems, and privacy-first approach. Built by communities for superior performance.
Typesense
GPL-3.0Open-source search solution offering blazing speed, typo tolerance, and effortless scalability for developers and businesses.
Tuta
GPL-3.0Tuta offers encrypted email, calendar and contacts with quantum-resistant security, protecting your privacy without ads or tracking.
Turso
MITTurso provides a simple developer experience with SQLite compatibility, allowing you to build and scale multi-tenant applications with unlimited databases.
Quiet
GPL-3.0Quiet 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.
Timeplus
Apache-2.0Timeplus is a lightweight, powerful, and cost-efficient stream processing platform for real-time analytics, deployed as a single binary.
TDengine
AGPL-3.0High-performance time-series database with industrial data management, built-in stream analytics, and AI-driven anomaly detection for operational environments.
T3 Code
MITAdvanced AI coding assistant that enhances development workflow with intelligent code suggestions, automated debugging, and seamless integration.
Tailscale
BSD-3-ClauseDeploy a modern WireGuard-based VPN with zero configuration. Connect devices securely across clouds, VPCs, and on-premises networks without firewall rules.
Kitty
GPL-3.0High-performance terminal emulator with GPU acceleration, graphics support, and advanced scripting capabilities for developers and system administrators.
Seafile
NOASSERTIONOpen source file sync and sharing platform with custom properties, AI automation, collaborative editing, and enterprise-grade security for teams.
Scalar
MITScalar is an open-source tool for building, customizing, and hosting interactive API documentation with OpenAPI support.
RustDesk
AGPL-3.0Cross-platform remote desktop software that runs on your own servers, giving you full data control as a direct alternative to TeamViewer and AnyDesk.
s&box
NOASSERTIONA game creation platform built on Valve's Source 2 engine, letting you build, share, and play games without leaving the environment.
RawTherapee
GPL-3.0Free, cross-platform raw image processor with 32-bit floating point engine, advanced demosaicing algorithms, and professional-grade editing tools for photographers.
Qdrant
Apache-2.0Qdrant is an open-source vector database that provides high-performance similarity search for AI and machine learning applications.
QuestDB
Apache-2.0Open-source time-series database offering massive ingestion throughput, millisecond queries, and SQL extensions, designed for optimal performance at any hardware scale.
Prismical
MITFree, open-source AI note-taker that transcribes meetings and voice notes locally using Whisper and Parakeet. Works on Mac, Windows, and mobile without invasive bots.
Proton Lumo
GPL-3.0AI chat assistant from Proton that stores conversations with zero-access encryption, never logs chats, and never uses your data to train models.
Organic Maps
NOASSERTIONFree, open-source offline maps app with detailed trails, turn-by-turn navigation, and zero tracking. Perfect for hikers, cyclists, and travelers seeking privacy.
OpenVPN
NOASSERTIONSecure 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.
OpenWispr
MITDictation app powered by OpenAI Whisper and NVIDIA Parakeet. Runs locally on macOS, Windows, and Linux with zero data retention and 100+ language support.
Ollama
MITRuns open-source language models locally with a simple setup, plus optional cloud access for larger models when local hardware isn't enough.
OBS Studio
GPL-2.0OBS Studio offers high-quality video recording and live streaming capabilities, supporting multiple platforms and providers.
Neon Postgres
Apache-2.0Cloud-native, auto-scaling Postgres with instant branching, bottomless storage, and pay-per-use pricing
MonoGame
NOASSERTIONBuild games in C# that run on Windows, macOS, Linux, iOS, Android, and major consoles. No royalties, no subscriptions, no runtime fees.
Milvus
Apache-2.0Open-source vector database optimized for similarity search, scaling to billions of vectors with minimal performance loss
Meetily
MITRecords, transcribes, and summarizes meetings entirely on your device using local AI. No bots, no cloud uploads, GDPR and HIPAA compliant by design.
Memgraph
NOASSERTIONMemgraph is a scalable, in-memory graph database solution offering high-performance computing and Neo4j compatibility.
Manticore Search
GPL-3.0Open source search database delivering 2.83x faster performance than Elasticsearch. Features vector search, SQL interface, and full-text capabilities.
LocalAI
MITRun LLMs, speech, image generation, and autonomous agents on your own hardware with an OpenAI-compatible API and 60+ swappable backends.
llama.cpp
MITC/C++ inference engine for large language models, supporting quantization, multi-GPU, Apple Silicon, and an OpenAI-compatible server across a wide range of hardware.
Krita
GPL-3.0Free and open source painting program built by artists for artists. Features professional brushes, layers, animation tools, and drawing assistants for all skill levels.
Ladybird
BSD-2-ClauseOpen source web browser with its own engine, built from scratch without Blink, WebKit, or Gecko. Non-profit backed, no search deals, no user monetization.
KeePassXC
NOASSERTIONKeePassXC is an open-source password manager that securely stores and manages sensitive information across Windows, macOS, and Linux.
Kdenlive
GPL-3.0Cross-platform non-linear video editor offering professional features for free. Edit videos on Linux, Windows, macOS, and BSD with advanced tools and effects.
Pearcleaner
NOASSERTIONMac app uninstaller that finds and removes associated files, orphaned leftovers, and development artifacts across macOS 13 and later.
Jellyfin
GPL-2.0Free, open source media server that lets you collect, manage, and stream your personal library to any device, with no fees, tracking, or vendor lock-in.
Apache IoTDB
Apache-2.0Apache 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.
Icinga
GPL-3.0Monitor networks, servers, and cloud environments with flexible open-source solution. Custom checks, fast alerts, and complete infrastructure control.
Hummingbot
Apache-2.0Automate crypto trading strategies with a powerful, customizable platform. Connect to multiple exchanges and optimize your market making.
Helium
GPL-3.0Chromium-based desktop browser with default ad and tracker blocking, no analytics, native !bangs, split view, and full MV2 extension support.
Tonkatsu Box
MITCross-platform collection manager for retro games, movies, TV shows, anime, manga, visual novels, and books with tier lists, visual boards, and import/export.
Godot
MITBuild 2D, 3D, and XR games with a full-featured engine that includes its own scripting language, scene editor, and export tools for multiple platforms.
Ghostty
MITExperience blazing-fast terminal performance with GPU acceleration and platform-native UI. Cross-platform compatibility meets modern design.
ShareX
GPL-3.0ShareX is a free, open-source program that captures or records any area of your screen and shares it with a single keypress, supporting various file types and destinations.
GDevelop
NOASSERTIONFree, open-source game engine with visual event system, AI tutor, and one-click publishing to Steam, iOS, Android, and web platforms.
FeatBit
MITFeatBit is a fast, scalable feature flag service that enables risk mitigation and fosters business growth through controlled feature releases.
Fincept Terminal
NOASSERTIONComprehensive financial data platform offering economic insights, market analysis, and portfolio management tools
OceanBase
Apache-2.0Scalable, high-availability database system supporting OLTP, OLAP, and hybrid transactional/analytical processing workloads.
Dragonfly
NOASSERTIONDragonfly is a high-performance, Redis-compatible in-memory data store that delivers up to 25x more throughput and 80% lower costs than legacy solutions.
DBeaver
Apache-2.0Cross-platform database management tool for exploring, editing, and querying SQL databases including MySQL, PostgreSQL, SQLite, MariaDB, and more.
Apache Cloudberry
Apache-2.0Leverage advanced analytics with a modern PostgreSQL kernel. 100% open source for robust data solutions.
ClickHouse
Apache-2.0High-performance columnar OLAP database system for real-time analytics on big data, with SQL support and linear scalability.
Checkmk
GPL-2.0Monitor your entire IT infrastructure with 2,000+ plugins, automated discovery, and scalable architecture. Open source and enterprise solutions available.
Ceph
NOASSERTIONCeph provides unified object, block, and file storage from a single cluster built on commodity hardware.
Bitwarden
NOASSERTIONBitwarden is an open source password manager that securely stores, shares, and autofills passwords across unlimited devices.
Arize Phoenix
NOASSERTIONOpen-source platform for LLM tracing, evaluation, and optimization. Features automatic instrumentation, prompt playground, and real-time AI application monitoring.
Midori Browser
MPL-2.0Midori Browser is a lightweight, fast, and secure browser that protects users' privacy, available for Windows, Linux, and Android.
Aptabase
AGPL-3.0Open-source, self-hostable analytics platform for mobile and desktop apps, prioritizing user privacy and data control.
AppFlowy
AGPL-3.0Open source collaborative workspace combining notes, databases, and AI with full data ownership, offline support, and self-hosting options.
Anthias
NOASSERTIONFree open-source digital signage software that turns Raspberry Pi or old PCs into powerful display solutions. Manage images, videos, and web content easily.
Amical
MITOpen source AI dictation app that transforms speech to text with context-aware formatting. Fast, accurate transcription for meetings, notes, and hands-free typing.
FluidVoice
GPL-3.0Free, open-source macOS dictation app that transcribes speech locally, polishes output with an on-device AI model, and adapts tone to whichever app you're typing into.
Elasticsearch
NOASSERTIONElasticsearch is an open-source, RESTful search engine designed for scalability, reliability, and easy management.
