C libraries

The HTTP client behind an enormous share of software — every protocol, every platform.

The cryptography and TLS library most of the internet depends on.

The DEFLATE compression library that gzip, PNG and countless formats are built on.

Xlib is the standard C library for interfacing with the X Window System (X11) on Unix-like operating systems. It allows applications to create and manage windows, handle user input events, draw graphics, and communicate with the X server.

A complete SQL database in a single file, embedded directly in your process.

libxml2 is a C library for parsing XML documents. It provides a comprehensive set of functions for reading, validating, navigating, and manipulating XML data efficiently, and supports standards like XPath, XInclude, and XPointer.

Jansson is a C library for encoding, decoding, and manipulating JSON data. It provides simple and intuitive APIs to parse JSON strings, build JSON objects, arrays, and write JSON to files or memory.

A tiny JSON parser in a single C file you can drop into any project.

Cross-platform access to graphics, audio, input and windowing for games and multimedia.

GTK (GIMP Toolkit) is a multi-platform toolkit for creating graphical user interfaces. In Python, GTK is accessible via the PyGObject library, allowing developers to build desktop applications with windows, dialogs, buttons, menus, and more.

The cross-platform async I/O library extracted from Node.js.

libpng is the official PNG reference library for C. It provides functions to read, write, and manipulate PNG (Portable Network Graphics) images, supporting compression, filtering, and color types.

libjpeg-turbo is a high-speed version of the standard JPEG image codec library, using SIMD instructions (MMX, SSE2, NEON, AltiVec) to accelerate JPEG compression and decompression.

OpenAL (Open Audio Library) is a cross-platform 3D audio API designed for efficient rendering of multichannel spatialized audio. It is used in games, simulations, and multimedia applications to provide immersive sound experiences.

Terminal user interfaces — windows, colours and keyboard handling in a text console.

Check is a unit testing framework for C that allows developers to write test cases for their code in a simple and structured way. It provides assertions, test fixtures, and test suites to ensure code correctness.

Unity is a cross-platform game engine that allows developers to create 2D, 3D, VR, and AR games. While Unity primarily uses C#, low-level plugins and performance-critical components can be developed using C or C++ for integration via Unity's Native Plugin Interface.

Poppler is a PDF rendering library based on the xpdf-3.0 code base. It provides tools and APIs to extract text, render pages, and manipulate PDF files in C and C++ applications.

MuPDF is a lightweight, high-performance PDF, XPS, and EPUB rendering library written in C. It allows text extraction, page rendering, and manipulation of PDF documents with minimal memory usage.

CMocka is a lightweight, modern unit testing framework for C. It provides a simple API for writing unit tests, mocking functions, and verifying behavior in C programs.

pthread (POSIX Threads) is a standard C library for creating and managing threads. It provides APIs for multithreading, synchronization, and concurrency control in C programs on POSIX-compliant systems.

Cairo is a 2D graphics library that supports vector graphics, including drawing shapes, text, and images. It provides high-quality rendering for multiple output targets such as screens, PDFs, SVGs, and image buffers.

FreeType is a C library for rendering fonts, supporting various font formats such as TrueType, OpenType, Type1, and CFF. It provides functionality to load, rasterize, and render glyphs for text display in applications.

LevelDB is a fast, lightweight, single-purpose key-value storage library written in C++. It provides ordered mapping from string keys to string values with support for batch writes, snapshots, and iterators.

bzip2 is a high-quality data compression library and tool that uses the Burrows-Wheeler algorithm and Huffman coding. It provides better compression ratios than traditional gzip for many types of files.

LZ4 is an extremely fast lossless compression algorithm and library. It focuses on compression and decompression speed while maintaining reasonable compression ratios, making it ideal for real-time applications and large data streams.

libwebsockets is a lightweight C library for building WebSocket servers, clients, and HTTP(S) servers. It supports asynchronous, event-driven communication over WebSocket and HTTP protocols.

libevent is a high-performance C library that provides asynchronous event notification. It allows applications to execute callbacks when file descriptors, signals, or timers become active, enabling scalable network servers and event-driven programs.

libev is a high-performance event loop library in C that provides asynchronous I/O, timers, signals, and child process handling. It is designed for efficiency and scalability in networked and event-driven applications.

GLFW is an open-source library for creating windows, contexts, and handling input and events in OpenGL, OpenGL ES, and Vulkan applications. It is designed to be simple, portable, and lightweight, ideal for graphics and game development.