* [LwESP](https://github.com/MaJerle/lwesp) - Lightweight ESP AT commands parser library to communicate with ESP8266 or ESP32 Wi-Fi module using AT commands.
* [libmemory](https://github.com/embeddedartistry/libmemory) - Memory management library with implementations for malloc(), free(), and other useful memory management functions.
* [lwmem](https://github.com/MaJerle/lwmem) - Lightweight dynamic memory manager library for embedded systems with memory constraints. It implements malloc, calloc, realloc and free functions.
* [lwprintf](https://github.com/MaJerle/lwprintf) - Lightweight printf library optimized for embedded systems.
* [Embedded_Printf](https://github.com/agaelema/Embedded_Printf) - Embedded version of the famous "printf( )" function. The idea is create an simple and efficient library to meet some common needs in embedded systems.
* [cli](https://github.com/letgo0007/cli) - CLI (Command Line Interface) example build in pure C. Designed for MCU, support block/non-block mode input.
* [terminal](https://github.com/JingoC/terminal) - Command Line Interface for microcontrollers. Flexible terminal settings allow you to integrate it with any microcontroller, without much effort.
* [ProMenu](https://github.com/marcinbor85/ProMenu) - Advanced Generic Application Menu Library. ProMenu Library is used for fast implementing advanced user menus. It supports nesting, numeric settings, text settings, boolean values and events. Library is implemented in C++ with build-in Arduino port, but it is easy to port to different architecture.
* [EmbeddedProto](https://github.com/Embedded-AMS/EmbeddedProto) - C++ Protocol Buffers implementation specifically suitable for ARM Cortex-M microcontrollers. It is small, reliable and easy to use.
* [protobuf-embedded-c](https://github.com/berezovskyi/protobuf-embedded-c) - Protocol buffers generator for resource constrained embedded applications written in the C programming language.
* [microrl](https://github.com/Helius/microrl) - Micro read line library for small and embedded devices with basic VT100 support.
* [TinyFrame](https://github.com/MightyPork/TinyFrame) - Simple library for building and parsing data frames for serial interfaces (like UART / RS232).
* [interchange](https://github.com/trussed-dev/interchange) - Request/response mechanism for embedded development, using atomics.
* [RadioHead](https://github.com/hallard/RadioHead) - Packet Radio library for embedded microprocessors.
* [Adafruit's RadioHead](https://github.com/adafruit/RadioHead) - Packet Radio library for embedded microprocessors with [docs](http://www.airspayce.com/mikem/arduino/RadioHead/).
* [pcg-c-basic](https://github.com/imneme/pcg-c-basic) - Code provides a minimal implementation of one member of the PCG family of random number generators, which are fast, statistically excellent, and offer a number of useful features.
* [pcg-c](https://github.com/imneme/pcg-c) - Code provides an implementation of the PCG family of random number generators, which are fast, statistically excellent, and offer a number of useful features.
* [trussed](https://github.com/trussed-dev/trussed) - Minimal, modular way to write cryptographic applications on microcontroller platforms (Rust).
* [wolfSSH](https://www.wolfssl.com/products/wolfssh/) - Lightweight SSHv2 client and server library written in ANSI C and targeted for embedded, RTOS, and resource-constrained environments - primarily because of its small size, speed, and feature set.
* [heatshrink](https://github.com/atomicobject/heatshrink) - Data compression library for embedded/real-time systems.
* [shoco](https://github.com/Ed-von-Schleck/shoco) - C library to compress and decompress short strings. It is very fast and easy to use. The default compression model is optimized for english words, but you can generate your own compression model.
* [ECL](https://github.com/Nonoum/ECL) - Embedded Compression Library is not only for embedded, it is mostly oriented for small data and has special optimized low-memory modes for restricted environments.
* [nnom](https://github.com/majianjia/nnom) - Neural Network on Microcontroller (NNoM) is a high-level inference Neural Network library specifically for microcontrollers.
* [uIP](https://github.com/adamdunkels/uip) - Very small implementation of the TCP/IP stack that is written by Adam Dunkels.
* [LwIP](http://savannah.nongnu.org/projects/lwip/) - Small independent implementation of the TCP/IP protocol suite that has been initially developed by Adam Dunkels. lwIP suitable for use in embedded systems with tens of kilobytes of free RAM and room for around 40 kilobytes of code ROM.
* [mongoose](https://github.com/cesanta/mongoose) - Embedded Web Server Library. It is a multi-protocol embedded networking library with functions including TCP, HTTP client and server, WebSocket client and server, MQTT client and broker and much more.
* [libevhtp](https://github.com/criticalstack/libevhtp) - Extremely-fast and secure embedded HTTP servers with ease.
* [libμhttpd](https://github.com/zhaojh329/libuhttpd) - Very flexible, lightweight and fully asynchronous HTTP server library based on libev and http-parser.
* [fat32](https://github.com/strawberryhacker/fat32) - Lighweight FAT32 file system written in C with no thirdparty dependencies. It requires a small port which provide functions for initializing, reading and writing to the MSD.
* [emfat](https://github.com/fetisov/emfat) - FAT32 emulation library for stm32f4.
* [SWupdate](https://github.com/sbabic/swupdate) - Software Update for Embedded Linux Devices to update system in field. SWUpdate supports local and OTA updates, multiple update strategies and it is designed with security in mind.
* [TouchGFX](https://www.touchgfx.com/product/overview/) - User-friendly graphical C++ tool integrated as a free tool in the STM32 ecosystem.
* [eGUI](https://github.com/NXPmicro/eGUI) - An eGUI embedded graphic library.
* [Embedded-graphics](https://github.com/embedded-graphics/embedded-graphics) - 2D graphics library that is focused on memory constrained embedded devices.
* [SGFX](https://github.com/rprata/sgfx) - Lightweight embedded library for displays and touchscreens providing everything required to build a fully featured embedded GUI.
* [GUIX](https://github.com/azure-rtos/guix) - Provides a complete, embedded graphical user interface (GUI) library and design environment, facilitating the creation and maintenance of all graphical elements needed by your device.
* [ttf2mesh](https://github.com/fetisov/ttf2mesh) - Library for TrueType font tessellation. Allows to convert font glyphs to mesh objects without rasterization.
* [lcd-image-converter](https://github.com/riuson/lcd-image-converter) - Tool to create bitmaps and fonts for embedded applications; allows you to create bitmaps and fonts, and transform them to "C" source format for embedded applications.
* [scmRTOS](https://github.com/scmrtos/scmrtos) - Tiny Real-Time Preemptive Operating System intended for use with Single-Chip Microcontrollers. scmRTOS is capable to run on tiny uCs with as small amount of RAM as 512 bytes. The RTOS is written on C++ and supports various platforms.
* [embox](https://github.com/embox/embox) - Configurable RTOS designed for resource constrained and embedded systems. Embox main idea is using Linux software without Linux.
* [RIOT](https://github.com/RIOT-OS/RIOT) - Real-time multi-threading operating system that supports a range of devices that are typically found in the Internet of Things (IoT): 8-bit, 16-bit and 32-bit microcontrollers. RIOT is based on the following design principles: energy-efficiency, real-time capabilities, small memory footprint, modularity, and uniform API access, independent of the underlying hardware (this API offers partial POSIX compliance).
* [Arm Mbed OS](https://github.com/ARMmbed/mbed-os) - Platform operating system designed for the Internet of Things. It includes all the features you need to develop a connected product based on an Arm Cortex-M microcontroller, including security, connectivity, an RTOS and drivers for sensors and I/O devices.
* [RT-Thread](https://github.com/RT-Thread/rt-thread) - RT-Thread was born in 2006, it is an open source, neutral, and community-based real-time operating system (RTOS). RT-Thread has Standard version and Nano version. For resource-constrained microcontroller (MCU) systems, the NANO kernel version that requires only 3KB Flash and 1.2KB RAM memory resources can be tailored with easy-to-use tools; And for resource-rich IoT devices, RT-Thread can use the on-line software package management tool, together with system configuration tools, to achieve intuitive and rapid modular cutting, seamlessly import rich software packages, thus achieving complex functions like Android's graphical interface and touch sliding effects, smart voice interaction effects, and so on.
* [libcanard](https://github.com/UAVCAN/libcanard) - Compact implementation of the UAVCAN/CAN protocol in C for high-integrity real-time embedded systems.
* [Apache NuttX Apps](https://github.com/apache/incubator-nuttx-apps) - Collection of tools, shells, network utilities, libraries, interpreters and can be used with the NuttX RTOS.