Cpp20 GitHub Repositories (2026) · Open Source Tools

🎮 · Jazz² Resurrection: Native C++ reimplementation of Jazz Jackrabbit 2

The Domain-Correct Quantities and Units Library for C++ — full quantity kind safety, ISO 80000 compliant, C++29 standardization candidate.

Jinja2 C++ (and for C++) almost full-conformance template engine implementation

A modern, fast, lightweight thread pool library based on C++2x

Fast, convenient JSON serialization and parsing in C++

Zodiac Engine (ZEngine) — open-source 3D rendering engine in C++20 with Vulkan

Static recompilation of a PSP game into a native executable. Vulkan and SDL3. Bring your own copy of the game.

Xeno Executor — free keyless Roblox script executor for Windows x64. Luau runtime, manual-map DLL injector, ImGui overlay (2026).

Implementation of async observable/observer (Reactive Programming) in C++ with care about performance and templates in mind in ReactiveX approach

C++20 concurrency framework with no compromises. Excellent performance, powerful features, and simple syntax.

Modern C++ actor framework based on std::execution, only requires C++20 - Turns your class into async service.

A modern C++ module-first build tool — written in pure C++23 modules, fully self-hosted

MQT DDSIM - A Quantum Circuit Simulator Based on Decision Diagrams

Feral programming language reference implementation

OutpostHD - Open source remake of Sierra On-Line's Outpost

🐈‍⬛ A runtime for C++26 w/out libC or POSIX. Smaller binaries, only arena allocators, SIMD, stronger type safety than STL, and value-based errors!

MQT Core - Reusable C++20 and Python libraries for quantum computing: the MQT Compiler Collection, built on MLIR and LLVM, together with decision diagrams, QIR execution, QDMI device access, SDK and HPC integrations, and structured benchmarks. It forms the backbone of the Munich Quantum Toolkit.

The AI-native database built for LLM applications, providing incredibly fast hybrid search of dense vector, sparse vector, tensor (multi-vector), and full-text.

AppCUI is a cross-platform TUI (Text User Interface / Terminal User Interface) / CUI (Console User Interface) framework designed to allow quick creation of both TUI Application and TUI Games. AppCUI is heavily based on C++20 standards and offers a multitude of widgets such as windows, buttons, checkboxes, radioboxes, comboboxes, listviews, treeviews, tab controls, image previewers, and many more.

Fast market-making engine in C++20 with deterministic replay