awesome cpp

A curated list of awesome C++ (or C) frameworks, libraries, resources, and shiny things. Inspired by awesome-... stuff.

• Awesome C++
  • Standard Libraries
  • Frameworks
  • Artificial Intelligence
  • Asynchronous Event Loop
  • Audio
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  • CLI
  • Compression
  • Concurrency
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• Software
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• Resources
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• Contributing - If you see a project or link here that is no longer maintained or is not a good fit, please submit a pull request to improve this document. Thank you!

C++ Standard Library - including STL Containers, STL Algorithm, STL Functional, etc.

• C++ Standard Library - A collection of classes and functions, which are written in the core language and part of the C++ ISO Standard itself.
• Standard Template Library - The Standard Template Library (STL).
• C POSIX library - A specification of a C standard library for POSIX systems.
• ISO C++ Standards Committee - ISO/IEC JTC1/SC22/WG21 - The C++ Standards Committee. website
• The GNU C Library - The purpose of this manual is to tell you how to use the facilities of the GNU C Library.

C++ generic frameworks and libraries.

• abseil-cpp - Abseil C++ Common Libraries. [Apache2]
• Apache C++ Standard Library - STDCXX, A collection of algorithms, containers, iterators, and other fundamental components. [retired] [Apache2]
• APR - Apache Portable Runtime. Another library of cross-platform utility functions. [Apache2]
• ASL - Adobe Source Libraries provides peer-reviewed and portable C++ source libraries. [MIT]
• AUI - Declarative UI toolkit for C++20. [MPL2]
• Boost ⚡ - A large collection of generic C++ libraries. [Boost] website
• BDE - The BDE Development Environment from Bloomberg Labs. [Apache2]
• C++ Workflow ⚡ - C++ Parallel Computing and Asynchronous Networking Engine. [Apache2]
• CGraph - A cross-platform DAG framework based on C++ without any 3rd-party. [MIT]
• Cinder - A community-developed, free and open source library for professional-quality creative coding. [BSD]
• Coost - A tiny boost library in C++11. [MIT]
• Cxxomfort - A small, header-only library that backports various facilities from more recent C++ Standards to C++03 and later. [MIT]
• Dlib ⚡ - A toolkit for making real world machine learning and data analysis applications in C++. [Boost] website
• EASTL - Electronic Arts Standard Template Library. [BSD]
• ETL - Embedded Template Library. [MIT]
• ffead-cpp - Framework for Enterprise Application Development. [Apache2]
• Folly - An open-source C++ library developed and used at Facebook. [Apache2]
• FunctionalPlus - Functional Programming Library for C++. Write concise and readable C++ code. [MIT]
• GLib - GLib provides the core application building blocks for libraries and applications written in C. [LGPL]
• itlib - A collection of std-like single-header C++ libraries [MIT]
• JUCE - An all-encompassing C++ class library for developing cross-platform software. [Core-Module: ISC, Rest: GPL2/GPL3/Proprietary] website
• Kigs framework - A free and open source C++ modular multi-purpose cross platform RAD framework. [MIT] website
• libPhenom - libPhenom is an eventing framework for building high performance and high scalability systems in C. [Apache2]
• LibSourcey - C++11 evented IO for real-time video streaming and high performance networking applications. [LGPL]
• LibU - A multiplatform utility library written in C. [BSD]
• libxutils - Simple and yet powerful cross-platform C library providing data structures, algorithms and much more. [MIT]
• Loki - A C++ library of designs, containing flexible implementations of common design patterns and idioms. [MIT]
• MiLi - Minimal headers-only C++ Library. [Boost]
• OpenFrameworks - A cross platform open source toolkit for creative coding in C++. [MIT] website
• PhotonLibOS - A comprehensive C++ framework featuring efficient user-space threading (coroutine with work-stealing), I/O, networking, RPC, HTTP, etc., and used extensively in Alibaba. It is compatible with C++ 14/17/20/23, Linux, MacOS, x86-64, ARM64, gcc and clang. [Apache2] website
• Qt ⚡ - A cross-platform application and UI framework. [GPL/LGPL/Proprietary] website
• Reason - A cross platform framework designed to bring the ease of use of Java, .Net, or Python to developers who require the performance and strength of C++. [GPL2]
• ROOT - A set of OO frameworks with all the functionality needed to handle and analyze large amounts of data in a very efficient way. Used at CERN. [LGPL]
• rpp - Minimal Rust-inspired C++20 STL replacement. [MIT]
• SaneCppLibraries - a set of C++ platform abstraction libraries for macOS, Windows and Linux. [MIT] website
• Seastar - An advanced, open-source C++ framework for high-performance server applications on modern hardware. [Apache-2.0 License] seastar.io
• Siv3D - Siv3D (OpenSiv3D) is a C++20 framework for creative coding (2D/3D games, media art, visualizers, and simulators). [MIT] website
• STLport - An exemplary version of STL. [Free]
• STXXL - Standard Template Library for Extra Large Data Sets. [Boost]
• tbox - A glib-like multi-platform c library. [Apache2] website
• Ultimate++ - A C++ cross-platform rapid application development framework. [BSD]
• Windows Template Library - A C++ library for developing Windows applications and UI components. [Public]
• xtd - Modern C++20 framework to create console (CLI), forms (GUI) and unit tests (xUnit) applications on Windows, macOS, Linux, iOS, Android, FreeBSD and Haiku. [MIT]
• Yomm2 - Fast, Orthogonal, Open multi-methods. Supersedes Yomm11 [Boost]

• ANNetGPGPU - A GPU (CUDA) based Artificial Neural Network library. [LGPL]
• btsk - Game Behavior Tree Starter Kit. [zlib]
• Evolving Objects - A template-based, ANSI-C++ evolutionary computation library which helps you to write your own stochastic optimization algorithms insanely fast. [LGPL]
• frugally-deep - Header-only library for using Keras models in C++. [MIT]
• Genann - Simple neural network library in C. [zlib]
• MXNet - Lightweight, Portable, Flexible Distributed/Mobile Deep Learning with Dynamic, Mutation-aware Dataflow Dep Scheduler; for Python, R, Julia, Scala, Go, JavaScript and more. website
• PyTorch - Tensors and Dynamic neural networks in Python with strong GPU acceleration. website
• flashlight - Flashlight is a fast, flexible machine learning library written entirely in C++. [BSD]
• Recast/Detour - (3D) Navigation mesh generator and pathfinder, mostly for games. [zlib]
• TensorFlow - An open source software library for numerical computation using data flow graphs. [Apache]
• Txeo - A modern C++ wrapper for TensorFlow. [Apache]
• oneDNN - An open-source cross-platform performance library for deep learning applications. [Apache] website
• CNTK - Microsoft Cognitive Toolkit (CNTK), an open source deep-learning toolkit. [Boost]
• tiny-dnn - A header only, dependency-free deep learning framework in C++11. [BSD]
• Veles - Distributed platform for rapid Deep learning application development. [Apache]
• Kaldi - Toolkit for speech recognition. [Apache]

• Asio - A cross-platform C++ library for network and low-level I/O programming that provides developers with a consistent asynchronous model using a modern C++ approach. [Boost] website
• Boost.Asio - A cross-platform C++ library for network and low-level I/O programming. [Boost] website
• C++ Actor Framework - An Open Source Implementation of the Actor Model in C++. [BSD-3-Clause] website
• Ichor - An event queue which focuses on thread safety and provides dependency injection. [MIT]
• libev - A full-featured and high-performance event loop that is loosely modelled after libevent, but without its limitations and bugs. [BSD and GPL]
• libevent - An event notification library. [BSD]
• libhv - Cross-platform event loop library. [BSD]
• libuv - Cross-platform asynchronous I/O. [BSD]
• promise-cpp - Header only library that implements Promise/A+ standard. [Anti-996]
• uvw - C++ wrapper for libuv. [MIT]
• uv-cpp - a simple interface, high-performance network library based on C++11. [MIT]

Audio, Sound, Music, Digitized Voice Libraries

• Amplitude Audio SDK - A cross-platform audio engine designed with the needs of games in mind. [Apache-2.0] website
• Aubio - A library for audio and music analysis.[GPL-3.0] website
• AudioFile - A simple C++ library for reading and writing audio files. [MIT]
• audioFlux - A C library for audio and music analysis, feature extraction. [MIT]
• dr_libs - Single file audio decoding libraries for C and C++. [Unlicense]
• FMOD - An easy to use crossplatform audio engine and audio content creation tool for games. [Free for non-commercial/Commercial]
• KFR - Fast, modern C++ DSP framework, FFT, FIR/IIR filters, Sample Rate Conversion. [GPL/Proprietary]
• LAME - LAME is a high quality MPEG Audio Layer III (MP3) encoder. [LGPL]
• libsndfile - C library with C++ wrapper for reading and writing files containing sampled sound through one standard library interface. [LGPL-2.1] website
• libsoundio - C library for cross-platform real-time audio input and output. [MIT] website
• Maximilian - C++ Audio and Music DSP Library. [MIT]
• OpenAL - Open Audio Library - A crossplatform audio API. [BSD/LGPL/Proprietary]
• miniaudio - Single file audio playback and capture library. [Unlicense] website
• ni-media - C++ library for reading and writing audio files. [MIT]
• Opus - A totally open, royalty-free, highly versatile audio codec. [BSD]
• PortAudio - PortAudio is a free, cross-platform, open-source, audio I/O library. [MIT]
• rnnoise - Recurrent neural network for audio noise reduction. [BSD-3-Clause]
• SELA - SimplE Lossless Audio. [MIT]
• SoLoud - Easy, portable audio engine for games. [zlib]
• Speex - A free codec for free speech. Obsoleted by Opus. [BSD]
• Tonic - Easy and efficient audio synthesis in C++. [Unlicense]
• Vorbis - Ogg Vorbis is a fully open, non-proprietary, patent-and-royalty-free, general-purpose compressed audio format. [BSD]
• minimp3 - Public domain, header-only MP3 decoder with clean-room implementation. [CC0]
• Verovio - Verovio is a fast and lightweight music notation engraving library. [LGPL] website
• Wav2Letter++ - Public domain, a fast open source speech processing toolkit written entirely in C++ and uses the ArrayFire tensor library and the flashlight machine learning library for maximum efficiency. [BSD]

Bioinformatics, Genomics, Biotech

• BioC++ - C++ Computational Libraries for Bioinformatics. [BSD]
• Chaste - An open source C++ library for the computational simulation of mathematical models developed for physiology and biology. [BSD]
• libsequence - A C++ library for representing and analyzing population genetics data. [GPL]
• SeqAn - Algorithms and data structures for the analysis of sequences with the focus on biological data. [BSD/3-clause]
• Vcflib - A C++ library for parsing and manipulating VCF files. [MIT]
• Wham - Structural variants (SVs) in Genomes by directly applying association tests to BAM files. [MIT]

• jech/dht - BitTorrent DHT library in C. [MIT]
• libtorrent (a.k.a. libtorrent-rasterbar) - An efficient feature complete C++ bittorrent implementation. [BSD]
• LibTorrent (a.k.a. libtorrent-rakshasa) - BitTorrent library. [GPL]
• libutp - uTorrent Transport Protocol library. [MIT]

Chemistry, Quantum Chemistry, Solid-State Chemistry/Physics, Geochemistry, Biochemistry

• d-SEAMS - A molecular dynamics trajectory analysis engine in C++ and Lua with Nix. It is an acronym for Deferred Structural Elucidation Analysis for Molecular Simulations. [GPL] website
• gromacs - A message-passing parallel molecular dynamics implementation. [GPL] website
• Reaktoro - A computational framework in C++ and Python for modeling chemically reactive systems. [LGPL] website
• LAMMPS - A classical molecular dynamics code with a focus on materials modeling. It's an acronym for Large-scale Atomic/Molecular Massively Parallel Simulator. [GPL] website
• MADNESS - Multiresolution Adaptive Numerical Environment for Scientific Simulation. [GPL] website
• MPQC - The Massively Parallel Quantum Chemistry program, MPQC, computes properties of atoms and molecules from first principles using the time independent Schrödinger equation. [GPL] website
• Psi - An ab initio computational chemistry package. [GPL] website

Console/Terminal User Interface, Command Line Interface

• Argh! - A minimalist, frustration-free, header-only argument handler. [BSD]
• argparse - Argument Parser for Modern C++. [MIT]
• args - A simple header-only C++ argument parser library. [MIT]
• barkeep - Small C++ header to display async animations, counters, and progress bars. [Apache-2.0] website
• Boost.Program_options - A library to obtain program options via conventional methods such as command line and config file. [Boost] website
• cli - A cross-platform header only C++14 library for interactive command line interfaces (Cisco style). [Boost]
• CLI11 - Header only single or multi-file C++11 library for simple and advanced CLI parsing. [BSD]
• clipp - Easy to use, powerful and expressive command line argument handling for C++11/14/17 contained in a single header file. [MIT]
• cpp-terminal - Small header only C++ library for writing multiplatform terminal applications. [MIT]
• Ctrl+C - Crossplatform C++11 library to handle Ctrl+C event in custom functions. [MIT]
• cxxopts - Lightweight C++ command line option parser. [MIT]
• docopt.cpp - A library to generate option parser from docstring. [MIT/Boost]
• FINAL CUT - Library for creating terminal applications with text-based widgets. [LGPL]
• FTXUI - C++ Functional Terminal User Interface. [MIT]
• gflags - Commandline flags module for C++. [BSD]
• imtui - Immediate Mode Text-based User Interface. [MIT]
• indicators - Activity indicators for Modern C++. [MIT]
• linenoise - A small self-contained alternative to readline and libedit. [BSD-2-Clause]
• linenoise-ng - A small, portable GNU readline replacement for Linux, Windows and MacOS which is capable of handling UTF-8 characters. [BSD]
• Lyra - A simple to use, composable, command line parser for C++ 11 and beyond. [Boost]
• Ncurses - A terminal user interface. [MIT]
• oof - Convenient, high-performance RGB color and position control for console output. [MIT]
• PDCurses - Public domain curses library with both source code and pre-compiled library available. [PublicDomain]
• popl - A single-header templated command line arguments and ini file parser for C++ 11 and beyond. [MIT]
• replxx - A readline and libedit replacement that supports UTF-8, syntax highlighting, hints, works on Unix and Windows. [BSD]
• tabulate - Table Maker for Modern C++. [MIT]
• TCLAP - A mature, stable and feature-rich library for defining and accessing command line arguments in ANSI C++. [MIT]
• termbox - A C library for writing text-based user interfaces. [MIT]
• TermOx - C++17 Terminal User Interface(TUI) Library. [MIT]
• tuibox - A single-header terminal UI (TUI) library, capable of creating mouse-driven, interactive applications on the command line. [MIT]

Compression and Archiving Libraries

• bit7z - A C++ static library offering a clean and simple interface to the 7-zip shared libraries. [MPL2]
• Brotli - Brotli compression format. Developed by Google. [MIT]
• bzip2 - A freely available, patent free, high-quality data compressor. [BSD]
• bzip3 - A better and stronger spiritual successor to BZip2. [LGPL]
• FastLZ - Small & portable byte-aligned LZ77 compression. [MIT]
• FiniteStateEntropy - New generation entropy codecs : Finite State Entropy and Huff0.
• heatshrink - data compression library for embedded/real-time systems [ISC]
• Kanzi - a modern, modular, portable and efficient lossless data compressor implemented in C++. [Apache-2.0]
• KArchive - A library for creating, reading, writing and manipulating file archives like zip and tar. It also provides transparent compression and decompression of data, using formats like gzip, via a subclass of QIODevice. [LGPL]
• libarchive - Multi-format archive and compression library. [New BSD] website
• LZ4 - Extremely Fast Compression algorithm. [BSD] website
• LZFSE - LZFSE compression library and command line tool. Developed by Apple.
• LZHAM - Lossless data compression library with a compression ratio similar to LZMA but with much faster decompression. [BSD]
• LZMA ⚡ - The default and general compression method of 7z format. [PublicDomain] website
• LZMAT - An extremely fast real-time lossless data compression library. [GPL]
• miniz - Single C source file Deflate/Inflate compression library with zlib-compatible API, ZIP archive reading/writing, PNG writing. [MIT]
• Minizip - Zlib with latest bug fixes that supports PKWARE disk spanning, AES encryption, and IO buffering. [zlib]
• minizip-ng - Fork of the popular zip manipulation library found in the zlib distribution. [zlib]
• PhysicsFS - A library to provide abstract access to various archives. It is intended for use in video games, and the design was somewhat inspired by Quake 3's file subsystem. [zlib]
• Rapidgzip - Gzip Decompression and Random Access for Modern Multi-Core Machines. [Apache-2/MIT]
• smaz - Small strings compression library. [BSD]
• Snappy - A fast compressor/decompressor. [BSD]
• ZLib - A very compact compression library for data streams. [zlib]
• zlib-ng - zlib for the "next generation" systems. Drop-In replacement with some serious optimizations. [zlib]
• zstd - Zstandard - Fast real-time compression algorithm. Developed by Facebook. [BSD]
• ZZIPlib - Provides read access on ZIP-archives. [MPL/LGPL]

Concurrency and Multithreading

• alpaka - Abstraction library for parallel kernel acceleration. [LGPLv3+]
• ArrayFire - A general purpose GPU library. [BSD]
• Async++ - A lightweight concurrency framework for C++11, inspired by the Microsoft PPL library and the N3428 C++ standard proposal. [MIT]
• Boost.Compute - A C++ GPU Computing Library for OpenCL. [Boost] website
• Bolt - A C++ template library optimized for GPUs. [Apache2]
• BS::thread_pool - A fast, lightweight, and easy-to-use C++17 thread pool library [MIT]
• Channel - Thread-safe container for sharing data between threads. [MIT]
• ck - Concurrency primitives, safe memory reclamation mechanisms and non-blocking data structures. [BSD]
• concurrentqueue - A fast multi-producer, multi-consumer lock-free concurrent queue for C++11. [BSD,Boost]
• Coros - An easy-to-use and fast library for task-based parallelism, utilizing coroutines. [BSL-1.0]
• CUB - CUB provides state-of-the-art, reusable software components for every layer of the CUDA programming mode. [New BSD]
• cuda-api-wrappers - Lightweight, Modern-C++ wrappers for the CUDA GPU programming runtime API. [BSD]
• cupla - C++ API to run CUDA/C++ on OpenMP, Threads, TBB, ... through Alpaka. [LGPLv3+]
• C++React - A reactive programming library for C++11. [Boost]
• FiberTaskingLib - Task-based multi-threading library that supports task graphs with arbitrary dependencies. [Apache]
• HPX - A general purpose C++ runtime system for parallel and distributed applications of any scale. [Boost]
• Intel Games Task Scheduler - A task scheduling framework designed for the needs of game developers. [MIT]
• Intel Parallel STL - Intel® implementation of C++17 STL for C++11 and above. [Apache2]
• Intel TBB - Intel® Threading Building Blocks. [Apache2]
• junction - A library of concurrent data structures in C++. [BSD]
• Kokkos - A performance portable programming model for parallel execution and memory abstraction. [BSD]
• libcds - A C++ library of Concurrent Data Structures. [BSD]
• Libclsph - An OpenCL based GPU accelerated SPH fluid simulation library. [MIT]
• libdill - Introduces structured concurrency in C. [MIT]
• libdispatch - Grand Central Dispatch (GCD), developed by Apple Inc., is a task parallelism technology based on the thread pool pattern. libdispatch is a library that provides the implementation of GCD's services. [Apache-2.0] website
• libfork - A bleeding-edge, lock-free, wait-free, continuation-stealing tasking library built on C++20's coroutines. [MPL-2.0] website
• libmill - Introduces Go-style concurrency in C. [MIT]
• marl - Marl is a hybrid thread / fiber task scheduler written in C++ 11. [Apache-2.0]
• moderngpu - moderngpu is a productivity library for general-purpose computing on GPUs. It is a header-only C++ library written for CUDA. The unique value of the library is in its accelerated primitives for solving irregularly parallel problems. [FreeBSD & Copyright, Sean Baxter]
• NCCL - Optimized primitives for collective multi-GPU communication. [BSD]
• Neco - Concurrency library for C (coroutines). [MIT]
• OpenCL - The open standard for parallel programming of heterogeneous systems.
• OpenMP - The OpenMP API.
• rotor - Event loop friendly C++ actor micro framework. [MIT]
• SObjectizer - An implementation of Actor, Publish-Subscribe, and CSP models in one rather small C++ framework. [BSD-3-Clause]
• Quantum - A powerful C++ coroutine dispatcher framework built on top of Boost.Coroutine2.
• RaftLib - The RaftLib C++ library, streaming/dataflow concurrency via C++ iostream-like operators. [Apache2]
• readerwriterqueue - A fast single-producer, single-consumer lock-free queue for C++. [BSD]
• stdgpu - Efficient STL-like Data Structures on the GPU. [Apache2]
• Taskflow - A General-purpose Parallel and Heterogeneous Task Programming System. (renamed from Cpp-Taskflow) [MIT]
• ThreadPool - A simple C++11 Thread Pool implementation [zlib]
• Thrust - A parallel algorithms library which resembles the C++ Standard Template Library (STL). [Apache2]
• transwarp - A header-only C++ library for task concurrency. [MIT]
• VexCL - A C++ vector expression template library for OpenCL/CUDA. [MIT]
• STAPL - A C++ parallel programming framework designed to work on both shared and distributed memory parallel computers. [BSD]
• concurrencpp - A general concurrency library containing tasks, executors, timers and C++20 coroutines to rule them all.

Configuration files, INI files

• inifile-cpp - A header-only and easy to use Ini file parser for C++. [MIT]
• inih - Simple .INI file parser in C, good for embedded systems. [BSD-3-Clause]
• inih - Single header only C++ version of inih. [BSD-3-Clause]
• ini-cpp - Single header only C++ version, with some handy read/write interface, extend from inih. [BSD-3-Clause] website
• iniparser - INI file parser. [MIT]
• inipp - Simple header-only C++ ini parser and generator. [MIT]
• libconfig - C, C++ library for processing structured configuration files. [LGPL-2.1] website
• libconfuse - Small configuration file parser library for C. [ISC]
• mINI - INI file reader and writer. [MIT]
• simpleini - Cross-platform C++ library providing a simple API to read and write INI-style configuration files. [MIT]
• toml++ - Header-only TOML parser and serializer for C++17 and later. [MIT] website
• toml11 - a C++11 (or later) header-only toml parser/encoder depending only on C++ standard library. [MIT]

• C++ B-tree - A template library that implements ordered in-memory containers based on a B-tree data structure. [Apache2]
• dynamic_bitset - Simple Useful Libraries: C++17/20 header-only dynamic bitset. [MIT] website
• fixed-containers - Header-only C++20 library that provides fixed capacity constexpr containers. [MIT]
• flat_hash_map - A very fast flat hashtable with Fibonacci hashing.
• frozen - a header-only, constexpr alternative to gperf for C++14 users. [Apache-2.0]
• Hashmaps - Implementation of open addressing hash table algorithms in C++. [MIT]
• hat-trie - C++ implementation of a fast and memory efficient HAT-trie. [MIT]
• Hopscotch map - A fast header-only hash map which uses hopscotch hashing for collisions resolution. [MIT]
• LSHBOX - A c++ toolbox of locality-sensitive hashing (LSH), provides several popular LSH algorithms, also support Python and MATLAB. [GPL]
• parallel-hashmap - A family of header-only, very fast and memory-friendly hashmap and btree containers [Apache2] website
• PGM-index - A data structure that enables fast lookup, predecessor, range searches and updates in arrays of billions of items using orders of magnitude less space than traditional indexes. [Apache2] website
• plf::colony - An unordered "bag"-type container which outperforms std containers in high-modification scenarios while maintaining permanent pointers to non-erased elements regardless of insertion/erasure. [zLib] website
• plf::list - A std::list implementation which removes range splicing in order to enable cache-friendlier structure, yielding significant performance gains. [zLib] website
• plf::stack - A replacement container for the std::stack container adaptor, with better performance than any std container in a stack context. [zLib] website
• ring_span lite - A simplified implementation of Arthur O'Dwyer's ring_span implementation ie. a circular buffer view. [MIT]
• robin-hood-hashing - Fast & memory efficient hashtable based on robin hood hashing for C++14. [MIT]
• robin-map - Fast hash map and hash set using robin hood hashing. [MIT]
• sparsepp - A fast, memory efficient hash map for C++. [BSD 3-clause]
• sqlitemap - Persistent map backed by SQLite. [MIT]
• st_tree - A fast and flexible c++ template class for tree data structures. [Apache-2.0]
• svector - Compact SVO optimized vector for C++17 or higher. [MIT]
• tree.hh - An STL-like C++ header-only tree library. [GPL2+]
• unordered_dense - A fast & densely stored hashmap and hashset based on robin-hood backward shift deletion. [MIT]

Cryptography and Encryption Libraries

• Bcrypt - A cross platform file encryption utility. Encrypted files are portable across all supported operating systems and processors. [BSD]
• BeeCrypt - A portable and fast cryptography library. [LGPLv2.1+]
• Botan - A crypto library for C++. [BSD-2]
• Crypto++ - A free C++ class library of cryptographic schemes. [Boost] website
• digestpp - C++11 header-only message digest (hash) library. [PublicDomain]
• GnuPG - A complete and free implementation of the OpenPGP standard. [GPL]
• GnuTLS - A secure communications library implementing the SSL, TLS and DTLS protocols. [LGPL2.1]
• Libgcrypt - A general purpose cryptographic library originally based on code from GnuPG. [LGPLv2.1+]
• LibreSSL - A free version of the SSL/TLS protocol forked from OpenSSL in 2014. [?]
• libsodium - P(ortable|ackageable) NaCl-based crypto library, opinionated and easy to use. [ISC]
• libhydrogen - A lightweight, secure, easy-to-use crypto library suitable for constrained environments. [ISC]
• LibTomCrypt - A fairly comprehensive, modular and portable cryptographic toolkit. [WTFPL]
• mbedTLS - An open source, portable, easy to use, readable and flexible SSL library, previously known as PolarSSL. [Apache2] website
• Nettle - A low-level cryptographic library. [LGPL]
• OpenSSL - A robust, commercial-grade, full-featured, and Open Source cryptography library. [Apache] website
• retter - A collection of hash functions, ciphers, tools, libraries, and materials related to cryptography.
• s2n - An implementation of the TLS/SSL protocols. [Apache]
• sha1collisiondetection - Library and command line tool to detect SHA-1 collision in a file. [MIT]
• Tink - A multi-language, cross-platform library that provides cryptographic APIs that are secure, easy to use correctly, and hard(er) to misuse. [Apache-2.0]
• Tiny AES in C - Small portable AES128/192/256 in C. [PublicDomain]
• Themis - crypto library for painless data security, providing symmetric and asymmetric encryption, secure sockets with forward secrecy, for mobile and server platforms. [Apache2]
• HEhub - A library for homomorphic encryption and its applications. [Apache2]

Libraries for parsing Comma Separated Value (CSV) files

• commata - Just another header-only C++17 CSV parser. [Unlicense]
• csv2 - Fast CSV parser for modern C++. [MIT]
• Csv::Parser - Compile-time and runtime CSV parser written in C++17. [Zlib]
• Fast C++ CSV Parser - Small, easy-to-use and fast header-only library for reading CSV files. [BSD-3-Clause]
• Glaze - High performance, header only, CSV library with reflection support. [MIT]
• lazycsv - A fast, lightweight and single-header csv parser for modern C++. [MIT]
• rapidcsv - An easy-to-use, header-only C++ CSV parser library. [BSD-3-Clause]
• ssp - A header only "csv" parser which is fast and versatile with modern C++ api. [MIT]
• Vince's CSV Parser - A fast, self-contained, streaming C++17 CSV parser with optional type-casting and statistics. [MIT]

Database Libraries, SQL Servers, ODBC Drivers, and Tools

• ClickHouse - C++ client for ClickHouse DBMS. [Apache2]
• CrossDB - Ultra High-performance Lightweight Embedded and Server OLTP RDBMS. [MPL-2.0] website
• DuckDB - in-process SQL OLAP Database Management System. [MIT] website
• hiberlite - C++ Object-relational mapping for sqlite3. [BSD]
• Hiredis - A minimalistic C client library for the Redis database. [BSD]
• Infinity - The AI-native database built for LLM applications, providing incredibly fast vector and full-text search. [Apache2]
• Kuzu - Embeddable property graph database management system built for query speed and scalability. Implements Cypher. [MIT] website
• Kvrocks - A distributed key value NoSQL database that uses RocksDB as storage engine and is compatible with Redis protocol. [Apache2]
• LevelDB - A fast key-value storage library written at Google that provides an ordered mapping from string keys to string values. [BSD]
• libpg_query - C library for accessing the PostgreSQL parser outside of the server environment. [BSD-3-Clause]
• libpqxx - The official C++ client API for PostgreSQL. [BSD-3-Clause]
• LMDB - Very fast embedded key/value store with full ACID semantics. [OpenLDAP]
• LMDB++ - C++11 wrapper for the LMDB embedded database library. [PublicDomain]
• mgclient - C/C++ Memgraph Client. [Apache2]
• MongoDB C Driver - MongoDB client library for C. [Apache2]
• MongoDB C++ Driver - C++ driver for MongoDB. [Apache2]
• MongoDB Libbson - A BSON utility library. [Apache2]
• MySQL++ - A C++ wrapper for MySQL's C API. [LGPL]
• nanodbc - A small C++ wrapper for the native C ODBC API. [MIT]
• ODB - An open-source, cross-platform, and cross-database object-relational mapping (ORM) system for C++. [GPLv2]
• redis3m - Wrapper of hiredis with clean C++ interface, supporting sentinel and ready to use patterns. [Apache2]
• Reindexer - Embeddable, in-memory, document-oriented database with a high-level Query builder interface. [Apache2] website
• RocksDB - Embedded key-value store for fast storage from facebook. [BSD]
• SimDB - High performance, shared memory, lock free, cross platform, single file, minimal dependencies, C++11 key-value store. [Apache2]
• SOCI - A database abstraction layer for C++. [Boost]
• Speedb - Community-led project: A RocksDB compliant high performance scalable embedded key-value store. [Apache2]
• SQLite - A completely embedded, full-featured relational database in a few 100k that you can include right into your project. [PublicDomain]
• SQLiteC++ - SQLiteC++ (SQLiteCpp) is a smart and easy to use C++ SQLite3 wrapper. [MIT]
• sqlite_modern_cpp - Header only C++14 wrapper around sqlite library. [MIT]
• sqlite_orm - SQLite ORM light header only library for modern C++. [AGPL + paid MIT]
• sqlpp11 - A type safe embedded domain specific language for SQL queries and results in C++. [BSD-2-Clause]
• TidesDB - High-performance, durable, transactional embedded storage engine designed for flash and RAM optimization. [MPL-2.0] website
• TileDB - Fast Dense and Sparse Multidimensional Array DBMS. [MIT] website
• TinyORM - Modern C++ ORM library. [MIT] website
• UnQLite - A self-contained, serverless, zero-configuration, transactional NoSQL engine. [BSD-2-Clause] website
• upscaledb - An embedded "typed" key/value store with a built-in query interface. [GPLv3]
• TigerBeetleDB C++ client (Community) - TigerBeetle is a financial accounting database designed for mission critical safety and performance to power the future of financial services. [BSL-1.0]
• Trilogy - a client library for MySQL-compatible database servers, designed for performance, flexibility, and ease of embedding. [MIT]
• UStore - Multi-Modal database for BLOBs, JSON, and graphs. [Apache2]
• Velox - A C++ vectorized database acceleration library aimed to optimizing query engines and data processing systems. [Apache-2.0] website

Data visualization Libraries

• gplot++ - Cross-platform header-only C++ plotting library that interfaces with Gnuplot. [MIT]
• matplotplusplus - C++ Graphics Library for Data Visualization. [MIT] website
• morphologica - C++ header-only graphing and data visualization with modern OpenGL. [Apache-2.0] website

Debugging Libraries, Memory Leak and Resource Leak Detection, Unit Testing

• backward-cpp - A beautiful stack trace pretty printer for C++. [MIT]
• Bencher - A suite of continuous benchmarking tools designed to catch performance regressions in CI. [MIT]/[Apache2]
• benchmark - Google provided small microbenchmark support library. [Apache2]
• Boost.Test - Boost Test Library. [Boost] website
• check - Check is a unit testing framework for C. [LGPL-2.1] website
• doctest - The lightest feature rich C++ single header testing framework. [MIT]
• Catch2 - A modern, C++-native, test framework for unit-tests, TDD and BDD. [Boost]
• Celero - C++ Benchmarking Framework. [Apache2]
• cpp-dump - A C++ library for debugging purposes that can print any variable, even user-defined types. [MIT]
• CppUTest - Unit testing and mocking framework for C/C++. [BSD-3-clause]
• CUTE - C++ Unit Testing Easier. [LGPL3]
• CMocka - unit testing framework for C with support for mock objects. [Apache2]
• CppBenchmark - Performance benchmark framework for C++ with nanoseconds measure precision. [MIT]
• Cpptrace - A simple, portable, and self-contained C++ stacktrace library supporting C++11 and greater. [MIT]
• CppUnit - C++ port of JUnit. [LGPL2]
• CrashCatch - Single-header crash reporting for C++ that logs stack traces and creates .dmp and .txt crash dumps. [MIT] website
• CTest - The CMake test driver program. [BSD]
• dbg-macro - A dbg(…) macro for C++. [MIT]
• DebugViewPP - Debug logging viewer. [Boost]
• Deleaker - A tool for resource leak detection, including memory, GDI and handle leaks.
• FakeIt - Simple mocking framework for C++. [MIT]
• fff - A micro-framework for creating fake C functions. [MIT]
• Google Mock - A library for writing and using C++ mock classes. [BSD]
• Google Test - Google C++ Testing Framework. [BSD]
• Hippomocks - Single-header mocking framework. [LGPL-2.1]
• IceCream-Cpp - Never use cout/printf to debug again [MIT]
• ig-debugheap - Multiplatform debug heap useful for tracking down memory errors. [BSD]
• libassert - The most over-engineered C++ assertion library. [MIT]
• libtap - Write tests in C. [GPL2]
• microprofile - Profiler with web-view for multiple platforms. [Unlicense]
• MinUnit - A minimal unit testing framework for C self-contained in a single header file. [MIT]
• nanobench - Simple, fast, accurate single-header microbenchmarking functionality for C++11/14/17/20. [MIT] website
• Nanotimer - A simple low-overhead cross-platform timer class for benchmarking. [zLib] website
• Nonius - A C++ micro-benchmarking framework. [CC]
• Remotery - Single C File Profiler with Web Viewer. [Apache2]
• snitch - Lightweight C++20 testing framework. [Boost]
• Touca - Open-source regression testing system that you can self-host. [Apache2] website
• UnitTest++ - A lightweight unit testing framework for C++. [MIT/X Consortium license]
• Unity - Simple Unit Testing for C. [MIT]
• utest.h - Single header unit testing framework for C and C++. [Unlicense]
• utl::profiler - Singe-header profiler for C++17. [MIT]
• μt - C++20 single header/single module, macro-free μ(micro)/Unit Testing Framework. [Boost]
• VLD - Visual Leak Detector. A free, robust, open-source memory leak detection system for Visual C++.

• Doxide - Modern documentation for modern C++, configure with YAML, output Markdown. [Apache 2.0] website
• doxygen ⚡ - The de facto standard tool for generating documentation from annotated C++ sources. [GPL2] website
• doxyrest - A compiler from Doxygen XML to reStructuredText for Sphinx. [MIT]
• hdoc - The modern documentation tool for C++. [AGPL/Proprietary] website
• Natural Docs - Natural Docs is an open source documentation generator for multiple programming languages. [AGPL/Proprietary] website
• Sphinx - Sphinx makes it easy to create intelligent and beautiful documentation. [BSD-2-Clause] website

Digital signal processing.

• DSPFilters - A collection of useful C++ classes for digital signal processing. [MIT]
• FFTW - A C library for computing the DFT in one or more dimensions. [GPL]
• iir1 - IIR Realtime C++ filter library. [MIT]
• kissfft - A Fast Fourier Transform (FFT) library that tries to Keep it Simple, Stupid. [BSD-3-Clause]
• pocketfft - FFT implementation based on FFTPack, but with several improvements. [BSD-3-Clause]
• wavelib - C implementation of 1D and 2D wavelet transforms. [BSD-3-Clause]

Libraries for parsing and manipulating font files.

• Fontconfig - Font configuration and customization library. [MIT] website
• FreeType - FreeType is a freely available software library to render fonts. [FTL & GPLv2]
• otfcc - A C library and utility used for parsing and writing OpenType font files. [Apache-2.0]
• harfbuzz - A text shaping engine. [Old MIT]
• libschrift - A lightweight TrueType font rendering library. [ISC]

• Acid - A high speed C++17 Vulkan game engine. [MIT]
• Allegro - A cross-platform library mainly aimed for video games and multimedia programming. [zlib]
• Axmol Engine - A cross-platform game engine for desktop, mobile, and XBOX (UWP), derived from Cocos2d-x-4.0. [MIT] website
• Cocos2d-x - A multi-platform framework for building 2d games, interactive books, demos and other graphical applications. [MIT]
• Corange - A game engine written in pure C, SDL and OpenGL. [BSD]
• crown - Crown is a general purpose data-driven game engine, written from scratch in orthodox C++ with a minimalistic and data-oriented design philosophy in mind. [MIT]
• delta3d - A robust simulation platform. [LGPL2]
• EnTT - Gaming meets modern C++. [MIT]
• GamePlay - A cross-platform native C++ game framework for creating 2D/3D mobile and desktop games. [Apache2]
• Godot - A fully featured, open source, MIT licensed, game engine. [MIT]
• Grit - Community project to build a free game engine for implementing open world 3D games. [MIT]
• Halley - A lightweight game engine written in C++14 with a "true" entity-component system. [Apache 2.0]
• Hazel Game Engine - Hazel is primarily an early-stage interactive application and rendering engine for Windows. [Apache-2.0 license]
• JNGL - 2D library for Linux, Windows, macOS, Android, iOS, Xbox, the Nintendo Switch and the Web. [zlib] website
• KlayGE - a cross-platform open source game engine with plugin-based architecture. [GPLv2] website
• nCine - A cross-platform 2D game engine with an emphasis on performance, written in C++11 and optionally scriptable in Lua. [MIT] website
• o3de - An open-source, real-time, multi-platform 3D engine based on Amazon Lumberyard. [Apache2] website
• OpenXRay - a community-modified X-Ray engine used in S.T.A.L.K.E.R. game series. [Modified BSD/non-commercial only]
• Oxygine - A cross-platform 2D C++ game engine. [MIT]
• Panda3D - A game engine, a framework for 3D rendering and game development for Python and C++ programs. [Modified BSD] website
• PixelGameEngine - The official distribution of olcPixelGameEngine, a tool used in javidx9's YouTube videos and projects. [OLC3]
• Polycode - A cross-platform framework for creative code in C++ (with Lua bindings). [MIT] website
• quakeforge - Actively maintained branch of the original Quake engine code with 20+ years of development. [GPL-2.0]
• raylib - A simple and easy-to-use library to enjoy videogames programming. [zlib/libpng] website
• Spring - A powerful free cross-platform RTS game engine. [GPLv2/GPLv3] website
• Torque2D - An open-source and cross-platform C++ engine built for 2D game development. [MIT] website
• Torque3D - An open-source C++ engine built for 3D game development. [MIT] website
• toy engine - toy is a thin and modular c++ game engine and offers simple expressive c++ idioms to design full featured 2D or 3D games in fast iterations.
• Urho3D - A free lightweight, cross-platform 2D and 3D game engine implemented in C++. Greatly inspired by OGRE and Horde3D. [MIT]
• ezEngine - Is a free, open-source game engine written in C++. Its philosophy is to be modular and flexible, such that it can be adapted to many different use cases. [MIT] website

• CXXGraph - free C++(17) graph header-only library for representation and algorithms execution. [AGPL-3.0]
• Graaf - A general-purpose lightweight C++20 graph library. [MIT] website

Graphic User Interface

• Boden - Native, mobile, cross-platform GUI Framework. [GPL/LGPL/Proprietary] website
• CEGUI - Flexible, cross-platform GUI library.
• Elements - Lightweight, fine-grained, resolution independent, modular GUI library. [MIT]
• FLTK - Fast, light, cross-platform C++ GUI toolkit. [LGPL2]
• FOX Toolkit - an open-source, cross-platform widget toolkit. [LGPL]
• GacUI - GPU Accelerated C++ User Interface, with WYSIWYG developing tools, XML supports, built-in data binding and MVVM features. [Ms-PL]
• GTK+ - A multi-platform toolkit for creating graphical user interfaces. [LGPL]
• gtkmm - The official C++ interface for the popular GUI library GTK+. [LGPL]
• imgui - Immediate Mode Graphical User Interface with minimal dependencies. [MIT]
• implot - Immediate Mode Plotting widgets for imgui. [MIT]
• iup - Multi-platform toolkit for building graphical user interfaces. [MIT]
• libui - Simple and portable (but not inflexible) GUI library in C that uses the native GUI technologies of each platform it supports. [MIT]
• MyGUI - Fast, flexible and simple GUI. [MIT]
• nana - Nana is a cross-platform library for GUI programming in modern C++ style. [Boost]
• NanoGui - A minimalistic cross-platform widget library for OpenGL 3.x or higher. [BSD]
• NAppGUI - SDK for building cross-platform desktop apps in ANSI-C. [MIT] website
• nuklear - A single-header ANSI C gui library. [PublicDomain]
• QCustomPlot - Qt plotting widget without further dependencies. [GPLv3]
• Qwt - Qt Widgets for Technical Applications. [Own based on LGPL]
• QwtPlot3D - A feature-rich Qt/OpenGL-based C++ programming library, providing essentially a bunch of 3D-widgets. [zlib]
• RmlUi - The HTML/CSS User Interface library evolved. Fork of libRocket. [MIT]
• Saucer - A modern, cross-platform C++ webview library. [MIT]
• Sciter - Sciter is an embeddable HTML/CSS/scripting engine aimed to be used as an UI layer of modern desktop applications. [Free/Commercial]
• Slint - Lightweight GUI toolkit for desktop and embedded. [GPL/Free/Proprietary] website
• TGUI - Cross-platform modern c++ GUI. [Zlib] website
• WebUI - Use any web browser as GUI, with your preferred language in the backend and HTML5 in the frontend. [MIT] website
• wxCharts - A library to create charts in wxWidgets applications. [MIT] website
• wxWidgets - A C++ library that lets developers create applications for Windows, Mac OS X, Linux and other platforms with a single code base. [Own LGPL]
• Yue - A library for creating native cross-platform GUI apps. [LGPLv2]

• assimp - Open Asset Import Library (assimp) is a cross-platform 3D model import library which aims to provide a common API for different 3D asset file formats. [BSD-3-Clause] website
• bgfx - A cross-platform rendering library. [BSD]
• Blend2D - 2D vector graphics engine powered by a JIT compiler. [Zlib] website
• Cairo - A 2D graphics library with support for multiple output devices. [LGPL2 or Mozilla MPL]
• C-Turtle - A C++11 header-only turtle graphics library acting as a CImg wrapper. [MIT]
• Diligent Engine - A modern cross-platform low-level 3D graphics library. [Apache2]
• DirectXTK - A collection of helper classes for writing DirectX 11.x code in C++. [MIT]
• GLFW - A simple, cross-platform OpenGL wrangling library. [zlib/libpng]
• GLFWPP - A thin modern C++17 header-only wrapper for GLFW. [MIT]
• Harfang 3D 3D visualization library usable in C++, Python, Lua and Go. Based on BGFX. [GPLv3/LGPLv3/Proprietary] website
• herebedragons - A basic 3D scene implemented with various engines, frameworks or APIs. [MIT] website
• Horde3D - A small 3D rendering and animation engine. [EPL]
• Ion - A small and efficient set of libraries for building cross-platform client or server applications that use 3D graphics. [Apache2] website
• Irrlicht - A high performance realtime 3D engine written in C++. [zlib]
• libigl - Simple C++ geometry processing library. [MPL2]
• LLGL - Low Level Graphics Library (LLGL) is a thin abstraction layer for the modern graphics APIs. [BSD-3-Clause]
• LunaSVG - a standalone SVG rendering library in C++. [MIT]
• magnum - Lightweight and modular C++11/C++14 graphics middleware for games and data visualization. [MIT] website
• micro-gl - Realtime, Embeddable, Headers Only C++11 CPU vector graphics. no STD lib, no FPU and no GPU required. [CUSTOM] website
• NanoVG - Antialiased 2D vector drawing library on top of OpenGL for UI and visualizations. [Zlib]
• Ogre 3D ⚡ - A scene-oriented, real-time, flexible 3D rendering engine (as opposed to a game engine) written in C++. [MIT] website
• OpenSceneGraph - An open source high performance 3D graphics toolkit. [OSGPL]
• OpenSubdiv - Pixar's library for evaluating and rendering subdivision surfaces on CPU and GPU. [Modified Apache2]
• OpenVDB - Library and tools for storing, editing, and rendering volumetric datasets. [MPL2]
• Panda3D - A framework for 3D rendering and game development for Python and C++. [BSD]
• Partio - Library for wrangling particle data, with support for most common file formats. [Modified BSD]
• Skia - A complete 2D graphic library for drawing Text, Geometries, and Images. [BSD] website
• ThorVG - a platform-independent portable library that allows for drawing vector-based scenes and animations, including SVG and Lottie. [MIT] website
• TinySpline - A small, yet powerful ANSI C library for interpolating, transforming, and querying arbitrary NURBS, B-Splines, and Bézier curves. [MIT]
• urho3d - Cross-platform rendering and game engine. [Many different, mostly MIT]
• Yocto/GL - Tiny C++ Libraries for Data-Driven Physically-based Graphics. [MIT]
• olive.c - Simple 2D Graphics Library. [MIT]

• Boost.GIL - Generic Image Library. [Boost] website
• BitmapPlusPLus - Simple and Fast header only Bitmap C++ library. [MIT]
• CImg - A small, open source, C++ toolkit for image processing. [Own LGPL or GPL]
• CxImage - An image processing and conversion library to load, save, display, transform BMP, JPEG, GIF, PNG, TIFF, MNG, ICO, PCX, TGA, WMF, WBMP, JBG, J2K images. [zlib]
• Dlib ⚡ - A modern C++11 machine learning, computer vision, numerical optimization, and deep learning toolkit. [Boost] website
• fpng - Super fast C++ .PNG writer/reader. [Unlicense]
• FreeImage - An open source library that supports popular graphics image formats and others as needed by today's multimedia applications. [GPL2 or GPL3]
• GD - GD Graphics Library, famously used in PHP for image loading/manipulation & thumbnail generation. [custom permissive license, requires mention in user docs] website
• DCMTK - DICOM Toolkit.
• GDCM - Grassroots DICOM library.
• ITK - An open-source, cross-platform system for image analysis. [Apache2 from ITK 4.0]
• [Jpegli][https://*github.**com/google/jpegli] - an improved JPEG encoder and decoder implementation. [BSD-3-Clause]
• Leptonica - Leptonica is an open source library containing software that is broadly useful for image processing and image analysis applications. [BSD-2-Clause] website
• libavif - Library for encoding and decoding .avif files. [BSD-2-Clause]
• libfacedetection - Open source library for face detection in images. The face detection speed can reach 1500FPS. [BSD]
• libjpeg-turbo - A JPEG image codec that uses SIMD instructions to accelerate baseline JPEG encoding and decoding. [IJG & BSD-3-Clause & zlib] website
• libjxl - JPEG XL image format reference implementation. [BSD-3-Clause]
• libpng - the reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. [libpng-2.0] website
• libspng - Simple, modern libpng alternative. [BSD-2] website
• libvips - A fast image processing library with low memory needs. [LGPL] website
• LodePNG - PNG encoder and decoder in C and C++. [Zlib]
• Magick++ - ImageMagick program interfaces for C++. [Apache2]
• MagickWnd - ImageMagick program interfaces for C. [Apache2]
• MozJPEG - Improved JPEG encoder. [BSD/BSD-3-Clause/ZLIB]
• OpenCV ⚡ - Open source computer vision. [Apache2] website
• OpenEXR - Cross-platform library for high dynamic range imaging. [Modified BSDF]
• OpenImageIO - Powerful image and texture wrangling library with support for a wide number of common lossy and RAW formats. [Modified BSD]
• OpenJPEG - an open-source JPEG 2000 codec written in C language. [BSD-2-Clause]
• QOI - The “Quite OK Image Format” for fast, lossless image compression. [MIT]
• SAIL - Easy-to-use cross-platform image decoding library with pluggable image codecs. [MIT]
• Simd - C++ image processing library with using of SIMD: SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2, AVX-512, VMX(Altivec) and VSX(Power7), NEON for ARM. [MIT]
• stb-image - STB single-header image loading library. [Public Domain]
• tesseract-ocr - An OCR engine. [Apache2]
• TinyDNG - Header-only Tiny DNG/TIFF loader and writer in C++. [MIT]
• TinyEXIF - Tiny ISO-compliant C++ EXIF and XMP parsing library for JPEG. [MIT]
• TinyTIFF - lightweight TIFF reader/writer library. [GPL-3.0]
• Video++ - A C++14 high performance video and image processing library. [MIT]
• VIGRA - A generic C++ computer vision library for image analysis. [MIT X11]
• VTK - Open-source, freely available software system for 3D computer graphics, image processing and visualization. [BSD]

• gettext - GNU 'gettext'. [GPL2]
• IBM ICU - A set of C/C++ and Java libraries providing Unicode and Globalization support. [ICU]
• libiconv - An encoding conversion library between different character encodings. [GPL]
• simdutf - Unicode routines (UTF8, UTF16, UTF32): billions of characters per second using SSE2, AVX2, NEON, AVX-512. [Apache-2/MIT]
• uni-algo - Unicode Algorithms Implementation for C/C++. [Unlicense or MIT]
• utf8.h - Single header utf8 string functions for C and C++. [Unlicense]
• utf8proc - A clean C library for processing UTF-8 Unicode data. [MIT]

• Apache Thrift - Efficient cross-language IPC/RPC, works between C++, Java, Python, PHP, C#, and many more other languages. Originally developed by Facebook. [Apache2]
• Boost.Interprocess - Header-only Boost library that supports kernel-level shared memory and memory-mapped files, with in-built synchronization mechanisms (semaphores, mutexes, and more). [Boost] website
• bRPC - bRPC is an Industrial-grade RPC framework using C++ Language, which is often used in high performance system such as Search, Storage, Machine learning, Advertisement, Recommendation etc. [Apache2] website
• Cap'n Proto - Fast data interchange format and capability-based RPC system. [MIT] website
• eCAL - Pub/sub, client/server, C++/Python/C#, various message protocols (protobuf, capnproto ..). [Apache2] website
• gRPC - A high performance, open source, general-purpose RPC framework. [BSD] website
• Ice - Comprehensive RPC framework with support for C++, C#, Java, JavaScript, Python and more. [GPLv2]
• iceoryx - True zero-copy inter-process communication framework for safety critical systems with bindings for C, Rust. Runs on Linux, QNX, Windows, Mac OS, FreeBSD. [Apache2] website
• libjson-rpc-cpp - JSON-RPC framework for C++ servers and clients. [MIT]
• nanomsg - A simple high-performance implementation of several "scalability protocols". [MIT] website
• nng - nanomsg-next-generation, a light-weight brokerless messaging library. [MIT] website
• rpclib - A modern C++ msgpack-RPC server and client library. [MIT]
• simple-rpc-cpp - A simple RPC wrapper generator to C/C++ functions. [BSD]
• SRPC - A lightweight RPC system that supports multiple protocols and OpenTelemetry. [Apache2]
• WAMP - Provides RPC and pub/sub messaging patterns. (various implementations, various languages)
• xmlrpc-c - A lightweight RPC library based on XML and HTTP. [BSD]

• Boost.PropertyTree - A property tree parser/generator that can be used to parse XML/JSON/INI/Info files. [Boost] website
• cJSON - Ultralightweight JSON parser in ANSI C. [MIT]
• DAW JSON Link - Fast, convenient JSON serialization and parsing in C++. [BSL-1.0]
• frozen - JSON parser and generator for C/C++. [GPL & GPL2]
• Glaze - Extremely fast, in memory, JSON and interface library for modern C++. [MIT]
• Jansson - C library for encoding, decoding and manipulating JSON data. [MIT]
• jbson - jbson is a library for building & iterating BSON data, and JSON documents in C++14. [Boost]
• JeayeSON - A very sane (header only) C++ JSON library. [BSD]
• Jsmn - A minimalistic JSON parser in C. [MIT]
• json ⚡ - JSON for Modern C++. [MIT] website
• JSON++ - A JSON parser in C++. [MIT]
• json.cpp - a baroque JSON parsing / serialization library for C++. [Apache-2.0]
• json.h - A simple one header/one source solution to parsing JSON in C and C++. [Unlicense]
• json-build - C89 tiny zero-allocation JSON serializer. [MIT]
• json-c - A JSON implementation in C. [MIT]
• jsoncons - A C++ header-only library for JSON and JSON-like binary formats with JSONPointer, JSONPatch, JSONPath and JMESPath. [Boost]
• JsonCpp - A C++ library for interacting with JSON. [MIT]
• Jsonifier - A few classes for parsing and serializing objects from/into JSON - very rapidly. [MIT]
• jsonParse - A simple JSON parser in ANSI C. [MIT]
• json-parser - Very low footprint JSON parser written in portable ANSI C. [BSD]
• json11 - A tiny JSON library for C++11. [MIT]
• json-struct - High performance, single header JSON parser parsing to and from C++ structs. [MIT]
• json-voorhees - JSON library for C++. Support for C++11. No dependencies, fast and dev-friendly. [Apache2]
• JSON Toolkit - JSON, JSON Pointer, JSON Schema, and JSONL library for C++20. [AGPL/Commercial]
• jute - Very simple C++ JSON Parser. [PublicDomain]
• libjson - A JSON parser and printer library in C. easy to integrate with any model. [LGPL]
• libjson - Lightweight JSON library. [?]
• LIBUCL ⚡ - Universal configuration library parser. [BSD-2-Clause]
• parson - Parson is a lighweight json library written in C. [MIT]
• PicoJSON - A header-file-only, JSON parser serializer in C++. [BSD]
• qt-json - A simple class for parsing JSON data into a QVariant hierarchy and vice versa. [GPLv3]
• QJson - A qt-based library that maps JSON data to QVariant objects. [LGPL2]
• RapidJSON ⚡ - A fast JSON parser/generator for C++ with both SAX/DOM style API. [MIT] website
• sajson - Lightweight, extremely high-performance JSON parser for C++11. [MIT]
• simdjson - Extremely fast JSON library that can parse gigabytes of JSON per second. [Apache-2.0]
• Sonic-Cpp - A fast JSON serializing & deserializing library, accelerated by SIM