Awesome header-only C++ libraries

• Argument Parsers
• Audio
• Benchmarking
• Communication
• Compression
• Concurrency
• Cryptography and Security
• Databases
• Data Formats
• Data Mining, Machine Learning, and Deep Learning
• Data Formatting and Presentation
• Data Querying
• Data Structures and Algorithms
• Debugging
• Deep Learning
• Dependency Injection
• Event Handling Mechanisms
• File System
• Functional Programming
• Geometry, Graphics Processing, and Game Development
• GPU
• Graph
• GUI
• High-performance Computing
• HTTP and the Web
• Image Processing
• Language Bindings
• Language Development
• Logging
• Mathematics
• Memory Management
• Mocking
• Networking
• Optimization
• Parsing
• Parsing Expression Grammars
• Portability Definitions
• Reflection
• Regular Expression
• Robotics
• Serialization
• SIMD
• Standard/Support Libraries
• State Machine
• Statistics
• String Utilities
• Templating Engines
• Terminal Utilities
• Testing Frameworks
• Unicode
• Units
• Validation
• Web Frameworks

Argument Parsers

Library	Stars	Description	License
Argh!		Argh! A minimalist argument handler.
argparse		Argument Parser for Modern C++.
args		A simple header-only C++ argument parser library.
cmd_line_parser		Command line parser for C++17.
CLI11		CLI11 is a command line parser for C++11 and beyond.
clipp		Powerful & Expressive Argument Parsing for Modern C++.
cxxopts		Lightweight C++ GNU style option parser library.
fire-hpp		Create fully functional CLIs using function signatures.
flags		Simple, extensible, header-only C++17 argument parser.
structopt		Parse command line arguments by defining a struct.

Audio

Library	Stars	Description	License
miniaudio		Audio playback and capture library written in C, in a single source file.
minimp3		Minimalistic MP3 decoder single header library.

Benchmarking

Library	Stars	Description	License
criterion		Microbenchmarking for Modern C++.
nanobench		Simple, fast, accurate microbenchmarking for C++11.
picobench		A small microbenchmarking library for C++11.

Communication

Library	Stars	Description	License
comms		Implement binary communication protocols in >=C++11.

Compression

Library	Stars	Description	License
Gzip		Gzip header-only C++ library.
interpolative_coding		Binary Interpolative Coding algorithm.
zstr		A C++ header-only ZLib wrapper.

Concurrency

Library	Stars	Description	License
cs_libguarded		Multithreaded programming.
taskflow		Modern C++ Parallel Task Programming.
task_system		Better Code: Concurrency - Sean Parent.
transwarp		A header-only C++ library for task concurrency.
taskpool		Modern C++ taskpool.
thread-pool		Modern C++20 thread-pool.

Cryptography and Security

Library	Stars	Description	License
cppcodec		Encode/decode base64, base64url, base32, etc.
digestpp		C++11 header-only message digest library.
PicoSHA2		Header-file-only, SHA256 hash generator in C++.
plusaes		Header only C++ AES cipher library.
stduuid		A C++17 cross-platform implementation for UUIDs.

Databases

Data Formats

Library	Stars	Description	License
bencode		C++20 bencode library.
Boost.JSON		JSON parsing, serialization, inspection and modification.
cpptoml		Header-only library for parsing TOML.
csv2		Fast CSV parser and writer for Modern C++.
CSV Parser		Reading, writing, and analyzing CSV files.
daw_json_link		Static JSON parsing in C++.
Fast C++ CSV Parser		Fast library for reading CSV files.
FlatJSON		Extremely fast just one allocation and zero copy JSON parser.
Glaze		Extremely fast, in memory, JSON and interface library for modern C++.
inih		This is a header only C++ version of inih.
nlohmann/json		JSON for Modern C++.
json_struct		High performance, single header only to serialize and deserialize JSON to C++ structs.
jsoncons		Construct JSON and JSON-like data formats.
minicsv		Bare minimal CSV stream based on C++ file streams.
picojson		a header-file-only, JSON parser serializer in C++.
pugixml		A C++ XML processing library with a DOM-like interface and XPath 1.0 support.
rapidcsv		C++ CSV parser library.
rapidjson		A fast JSON parser/generator for C++.
rapidxml		RapidXML fork; XML namespacing, per-element parsing, etc.
simdjson		Parsing gigabytes of JSON per second.
simpleini		Read and write INI-style configuration files.
taocpp JSON		C++ header-only JSON library.
toml11		TOML for Modern C++.
tomlplusplus		TOML config file parser and serializer for >=C++17.
tortellini		A really stupid INI file format for C++11.
valijson		JSON Schema validation.
xml2json		A header-only C++ library converts XML to JSON.

Data Mining, Machine Learning, and Deep Learning

Library	Stars	Description	License
dlib		A toolkit for real-world machine learning and data analysis.
frugally deep		Use Keras models in C++.
gaenari		Incremental decision tree in C++17.
hnswlib		Fast approximate nearest neighbors.
MiniDNN		A header-only C++ library for deep neural networks.
mlpack		mlpack: a fast, header-only C++ machine learning library.
nanoflann		Nearest Neighbor (NN) search with KD-trees.
tiny-dnn		Dependency-free deep learning framework in C++14.

Data Formatting and Presentation

Library	Stars	Description	License
asap		Creating, displaying, iterating and manipulating dates.
cxx prettyprint		Pretty-printing of any container in C++(0x).
emio		A safe and fast high-level and low-level character input/output C++20 library.
fmt		A modern formatting library.
pprint		Pretty Printer for Modern C++.
strf		A fast formatting library for C++14.
tabulate		Table Maker for Modern C++.

Data Querying

Library	Stars	Description	License
boolinq		Simplest C++ header-only LINQ template library.

Data Structures and Algorithms

Library	Stars	Description	License
BitMagic		Compressed bit-vectors, logical operations, memory compact containers.
concurrent queue		Fast multi-producer, multi-consumer lock-free concurrent queue.
dynamic bitset		The C++17 header-only dynamic bitset.
frozen		Constexpr alternative to gperf for C++14 users.
hopscotch map		Fast hash map and hash set using hopscotch hashing.
immer		Postmodern immutable and persistent data structures.
MPMCQueue		A bounded multi-producer multi-consumer concurrent queue.
outcome		Lightweight outcome and result.
parallel hashmap		Very fast and memory-friendly hashmap and btree containers.
PGM-index		Blazing fast queries and updates over billions of items using orders of magnitude less memory than other containers.
robin-hood hashing		Fast & memory efficient hashtable based on robin hood hashing.
robin-map		Fast hash map and hash set using robin hood hashing.
sfl-library		Small vector. Small flat map/multimap/set/multiset (ordered and unordered). C++11.
small		Implementations of the main STL containers optimized for the case when they are small.
tries		Fast and highly customisable C++20 trie implementation.

Debugging

Library	Stars	Description	License
backward-cpp		A beautiful stack trace pretty printer for C++.

Deep Learning

Library	Stars	Description	License
ceras		A deep learning engine in C++20.

Dependency Injection

Library	Stars	Description	License
inversify-cpp		C++17 inversion of control and dependency injection container library.

Event Handling Mechanisms

Library	Stars	Description	License
eventbus		Mediator pattern event bus for C++.
eventpp		Event Dispatcher and callback list for C++.
periodic-function		Callbacks at a specified time interval.

File System

Library	Stars	Description	License
simplebinstream		C++ Simplistic Binary Stream.
filesystem		Cross-platform implementation of std::filesystem for C++11/14/17.
glob		Glob for C++17.
llfio		P1031 low-Level file i/o and filesystem library.
mio		Cross-platform C++11 memory mapped file IO.
mm_file		Memory-mapped files for C++.
tinydir		Lightweight, portable C directory and file reader.

Functional Programming

Library	Stars	Description	License
FunctionalPlus		Functional Programming Library for C++.
immer		Persistent functional data structures in C++.
lager		Redux-like unidirectional data-flow for C++.
schmutz		Easy Guile Scheme C++ bindings.
zug		Transducers (from Clojure) in C++.

Geometry, Graphics Processing, and Game Development

Library	Stars	Description	License
arcball_camera		Immediate-mode camera for your graphics demos.
Brutus		Marching cubes implementation.
cinolib		Process polygonal and polyhedral meshes.
cr		A Simple C Hot Reload Header-only Library.
CxxSwizzle		Modern C++ swizzling header-only library.
earcut.hpp		Fast Polygon triangulation.
entt		Entity component system (ECS) and much more.
glm		OpenGL Mathematics (GLM).
librg		🚀 Making multi-player gamedev simpler since 2017.
micro-gl		👾 CPU Vector Graphics Engine (No FPU or std-lib needed).
nanort		Modern ray tracing kernel.
px		Thread Scheduling, Rendering, and so on.
Simple OpenGL Loader		Extensible, cross-platform OpenGL loader.
Sokol		Cross-platform libraries for C and C++.
stb		Single-file public domain libraries.
Swarmz		Swarming (flocking) library for real-time applications.
tiny-differentiable-simulator		Tiny Differentiable Simulator is a header-only C++ physics library with zero dependencies.
tinygltf		C++11 tiny glTF 2.0 library.
tweeny		A modern C++ tweening library.
Vookoo		Take the pain out of Vulkan.
voxelizer		Header only mesh voxelizer in c99.

GPU

Library	Stars	Description	License
thrust		Parallel programming library.
vuda		Vulkan-based library that provides a CUDA Runtime API interface for writing GPU-accelerated applications.
muda		Elegant kernel launch, debug-friendly memory accessor, automatic CudaGraph generation & updating for CUDA.

Graph

Library	Stars	Description	License
CXXGraph		Graph Representation and Algorithms Library >= C++17
Graaf		A general-purpose lightweight C++20 graph library.

GUI

Library	Stars	Description	License
Centurion		A modern C++17/20 wrapper library for SDL2.
GuiLite		The smallest header-only GUI library(5 KLOC) for all platforms.
Nuklear		Immediate mode cross-platform GUI library.
WinLamb		C++11 native Win32 GUI library.

High-performance Computing

Library	Stars	Description	License
MPL		A C++11 message passing library based on the Message Passing Interface standard.

HTTP and the Web

Library	Stars	Description	License
cinatra		Modern (c++17), Cross-platform Http Framework.
cpp-httplib		A C++11 Cross platform HTTP/HTTPS library.
jwt-cpp		Create and validate JSON web tokens.
RESTinio		Asynchronous HTTP/WebSocket server C++14 library
cuehttp		Modern c++ middleware framework for http(http/https)/websocket(ws/wss).
libfv		libfv is C++20 header-only network library, support TCP/SSL/Http/websocket server and client
NetIF		Cross-platform network interface addresses without name lookups in C++14.

Image Processing

Library	Stars	Description	License
BitmapPlusPlus		Simple and Fast header only Bitmap (BMP) library.
CImg		Cool Image, one file: full featured image processing.
color-util		Colors, Color space converters for RGB, HSL, XYZ, Lab, etc.
color		Color manipulation/conversion for different types and formats.
nanopm		NanoPM, single header only PatchMatch.

Language Bindings

Library	Stars	Description	License
jni.hpp		A modern, type-safe, C++14 wrapper for JNI.
pybind11		Seamless operability between C++11 and Python.
Selene		Simple C++11 friendly bindings to Lua.
Sol		Sol3 (sol2 v3.0) - a C++ <-> Lua API wrapper with advanced features and top notch performance.
v8pp		Bind C++ functions and classes into V8 JavaScript engine.

Language Development

Library	Stars	Description	License
Command Interpreter		Add a command interpreter (eg., REPL) to any C++ program.

Logging

Library	Stars	Description	License
easyloggingpp		Single header C++ logging library.
plog		Portable, simple and extensible C++ logging library.
spdlog		Fast C++ logging library.

Mathematics

Library	Stars	Description	License
amgcl		Solve large sparse linear systems with algebraic multigrid method.
dj_fft		FFT library.
eigen		Template library for linear algebra.
exprtk		C++ Mathematical Expression Toolkit.
fpm		Fixed-point math library.
kfr		Fast DSP framework, FFT, Sample Rate Conversion, etc.
libmorton		Methods to efficiently encode/decode Morton codes in/from 2D/3D coordinates.
linalg		Short vector math library for C++.
matplotlib-cpp		C++ plotting library built on the popular matplotlib.
matrix		A 2D matrix lib in C++20.
NumCpp		C++ implementation of the Python Numpy library.
random		Random for modern C++ with convenient API.
spectra		A header-only C++ library for large scale eigenvalue problems.
universal		Universal Number Arithmetic.

Memory Management

Library	Stars	Description	License
ugc		Incremental garbage collector.

Mocking

Library	Stars	Description	License
FakeIt		C++ mocking made easy.
trompeloeil		C++14 mocking framework.

Networking

Library	Stars	Description	License
asio		Asio C++ Library.
asio-grpc		Asynchronous gRPC with Asio/unified executors.
brynet		Cross-platform C++ TCP network library.
cppzmq		Header-only C++ binding for libzmq.
nygma		Network packet processing and indexing.
uvw		libuv wrapper in modern C++.

Optimization

Library	Stars	Description	License
ensmallen		C++ library for numerical optimization.

Parsing

Library	Stars	Description	License
lexertl14		The Modular Lexical Analyser Generator.
Matcheroni & Parseroni		C++20 libraries for doing pattern matching using Parsing Expression Grammars
parsertl14		The Modular Parser Generator.

Parsing Expression Grammars

Library	Stars	Description	License
cpp-peglib		PEG (Parsing Expression Grammars) library.
lug		A C++17 embedded domain specific language for expressing parsers as extended PEG.
PEGTL		Parsing Expression Grammar Template Library.

Portability Definitions

Library	Stars	Description	License
hedley		Move #ifdefs out of your code.

Reflection

Library	Stars	Description	License
better-enums		C++ compile-time enum to string, iteration.
magic_enum		Static reflection for enums.
meta		Macro-free runtime reflection system.
nameof		Nameof operator for modern C++.
refl-cpp		Compile-time reflection library.
visit_struct		A miniature library for struct-field reflection.

Regular Expression

Library	Stars	Description	License
compile-time regular expressions		A Compile time regular expression matcher.
SRELL		A ECMAScript (JavaScript) compatible regular expression engine.

Robotics

Library	Stars	Description	License
manif		Small library for Lie theory.

Serialization

Library	Stars	Description	License
alpaca		Serialization library written in C++17.
cereal		A C++11 library for serialization.
essentials		Transparent serialization/deserialization.
fuser		Automatic (de)serialization of C++ types to/from JSON.
YAS		A C++11 (de)serialization library with support for binary/text/json archives.
cista		simple, high-performance, zero-copy C++ serialization & reflection library.

SIMD

Library	Stars	Description	License
libsimdpp		Low-level SIMD library.
simde		Implementations of SIMD instruction sets.
tsimd		Fundamental C++ SIMD types for Intel CPUs.

Standard/Support Libraries

Library	Stars	Description	License
bitflags		Easily managing set of flags.
cpp-typelist		Modern typelist for C++20
expected		C++11/14/17 std::expected.
expected-lite		Expected objects in C++11 and later.
flux		A C++20 library for sequence-orientated programming.
gsl		ISO C++ Guidelines Support Library (GSL) by Microsoft.
gsl-lite		ISO C++ Guidelines Support Library (GSL).
hana		Your standard library for metaprogramming.
itlib		Standard-library-like containers and extensions.
leaf		Lightweight Error Augmentation Framework.
libunifex		Unified Executors
match(it)		A lightweight pattern-matching library for C++17 with macro-free APIs.
mp11		C++11 metaprogramming library.
NanoRange		Range-based goodness for C++17.
numeric_ranges		Numeric algorithms for C++20 Ranges.
optional		C++11/14/17 std::optional.
optional-lite		A C++17-like optional for C++98/11 and later.
range-v3		Range library for C++14/17/20.
rangesnext		Tanges features for c+23 ported to C++20.
span-lite		A C++20-like span for C++98/11 and later.
string-view-lite		A C++17-like string_view for C++98/11 and later.
uberswitch		Alternative to the C++ switch statement.
variant-lite		A C++17-like variant for C++98/11 and later.
Windows Implementation Libraries (WIL)		Readable type-safe C++ interfaces for common Windows coding patterns.

State Machine

Library	Stars	Description	License
hfsm2		High-performance hierarchical finite state machine framework.
hsm		Finite state machine library based on the boost hana.
tinyfsm		A simple C++ finite state machine library.
SMLite		State machine library for C, C++, C#, Java, JavaScript, Python, VB.Net.
cuestate		C++ template metaprogramming FSM.

Statistics

Library	Stars	Description	License
histogram		Multi-dimensional generalized histograms.
kalman		Kalman Filtering Library (EKF, UKF) based on Eigen3.
stats		Statistical distribution functions.

String Utilities

Library	Stars	Description	License
utf-cpp		UTF-8/16/32 for Windows/Linux/MacOs.
wildcards		String matching using wildcards.

Templating Engines

Library	Stars	Description	License
inja		A Template Engine for Modern C++.

Terminal Utilities

Library	Stars	Description	License
indicators		Activity Indicators for Modern C++.
rang		A Minimal library for terminal goodies 💄✨.
termcolor		Print colored messages to the terminal.

Testing Frameworks

Library	Stars	Description	License
ApprovalTests.cpp		Native ApprovalTests for C++.
Catch2		Test framework for unit-tests, TDD and BDD.
doctest		The fastest feature-rich C++11/14/17/20 testing framework.
iutest		Test framework for unit-tests.
lest		Tiny framework for unit-tests, TDD and BDD.
snitch		Lightweight C++20 testing framework.
ut		UT: C++20 μ(micro)/Unit Testing Framework.

Unicode

Library	Stars	Description	License
cpp-unicodelib		C++17 Unicode library.
uni-algo		Unicode algorithms for C++17.

Units

Library	Stars	Description	License
LLNL/units		Run-time unit representation and conversion.
mpusz/units		Compile-time dimensional analysis and unit/quantity manipulation.
nholthaus/units		Dimensional analysis and unit conversion library.
SI		Type safety and user defined literals for physical units.

Validation

Library	Stars	Description	License
cpp-validator		C++ library for data validation.

Web Frameworks

Library	Stars	Description	License
crow		Micro web framework inspired by Python Flask.