Topics / #header-only

Header-only projects on GitHub

C++ libraries distributed as headers only, requiring no separate compilation step.

As of October 18, 2026, the most-starred Header-only projects on GitHub are json (50.8K stars), stb (34.8K stars) and spdlog (29.7K stars). GitHub.Locker tracks 15 Header-only repositories with 280K stars combined. The fastest-growing on October 16 was clay, with +8 stars in a day.

15Projects

280KStars in total

+34Stars in a day

Browse in the catalog →github.com/topics/header-only ↗

Hot right now

Most stars gained in a day · Oct 16

clay

nicbarker/clay · ★ 18.3K

Clay (short for C Layout) is a high performance 2D UI layout library in C. You describe your UI with React-like declarative macros, it computes element positions and sizes in microseconds, and hands you back render commands.

json

nlohmann/json · ★ 50.8K

A JSON library for Modern C++ (nlohmann/json) that lets you read, create, and manipulate JSON values with intuitive, STL-like syntax directly in C++ code.

entt

skypjack/entt · ★ 13.2K

EnTT is a fast, header-only entity component system (ECS) for modern C++ game programming, plus a bunch of related utilities like reflection, event dispatching, and resource management.

Nuklear

Immediate-Mode-UI/Nuklear · ★ 11.5K

Nuklear is a minimal-state, immediate-mode graphical user interface toolkit written in ANSI C, designed as a simple embeddable UI that you build into your own application.

The all-time top

15 projects · by stars

#1 · nlohmann/json
json
A JSON library for Modern C++ (nlohmann/json) that lets you read, create, and manipulate JSON values with intuitive, STL-like syntax directly in C++ code.
50.8K
#2 · nothings/stb
stb
A collection of 21 single-file libraries for C/C++ covering image loading, writing and resizing, font rasterizing, audio decoding, containers and more — all released into the public domain, with an MIT option if you need a regular license.
34.8K
#3 · gabime/spdlog
spdlog
spdlog is a very fast C++ logging library. It ships header-only or as a compiled library, and its message formatting is powered by the fmt library.
29.7K

4
fmt
25.9Kfmtlib/fmt · C++
{fmt} is an open-source C++ formatting library — a fast, safe alternative to C stdio and C++ iostreams, with a format string syntax similar to Python's.
5
clay
18.3Knicbarker/clay · C
Clay (short for C Layout) is a high performance 2D UI layout library in C. You describe your UI with React-like declarative macros, it computes element positions and sizes in microseconds, and hands you back render commands.
6
pybind11
18Kpybind/pybind11 · C++
pybind11 is a lightweight header-only C++ library that exposes C++ types in Python and vice versa — mainly to create Python bindings for existing C++ code.
7
cpp-httplib
16.9Kyhirose/cpp-httplib · C++
A C++11 single-file header-only HTTP/HTTPS server and client library — you add networking to a C++ program by including one header, httplib.h.
8
rapidjson
15.1KTencent/rapidjson · C++
RapidJSON is a fast, header-only JSON parser and generator library for C++, supporting both SAX and DOM style APIs.
9
entt
13.2Kskypjack/entt · C++
EnTT is a fast, header-only entity component system (ECS) for modern C++ game programming, plus a bunch of related utilities like reflection, event dispatching, and resource management.
10
concurrentqueue
12.5Kcameron314/concurrentqueue · C++
moodycamel::ConcurrentQueue is an industrial-strength, lock-free multi-producer multi-consumer queue for C++11.
11
taskflow
12.2Ktaskflow/taskflow · C++
Taskflow is a C++ library that helps you write high-performance task-parallel programs with high programming productivity, letting you build and run graphs of dependent tasks across CPU threads and GPUs.
12
Nuklear
11.5KImmediate-Mode-UI/Nuklear · C
Nuklear is a minimal-state, immediate-mode graphical user interface toolkit written in ANSI C, designed as a simple embeddable UI that you build into your own application.
13
sokol
10.4Kfloooh/sokol · C
Sokol is a collection of minimal, cross-platform, standalone C header libraries for building apps and games: 3D graphics, windowing and input, audio, time, async file loading and argument parsing.
14
DeepEP
10.3Kdeepseek-ai/DeepEP · Cuda
DeepEP is a high-performance communication library for MoE (mixture-of-experts) models, providing fast all-to-all GPU kernels for expert-parallel dispatch and combine operations used in ML training and inference.
15
umium
436hotline1337/umium · C++
Umium is a security-focused anti-debugging and anti-reverse-engineering library for high-resilience Windows 10/11 x64 applications. It uses undocumented Windows NT system functions and runtime modifications to detect and neutralize debugging, memory tampering, or sandboxing attempts.