Mbed is a development platform and operating system for internet-connected devices (Internet of Things devices) based on 32-bit ARM Cortex-M microcontrollers. The project was a collaboratively developed by Arm and its technology partners. As of July 2024 Mbed is no longer actively developed by Arm.

The full version is a real-time operating system (RTOS) while more resource constrained devices can opt to use a non-RTOS subset.

The platform offers a development environment that includes:

The primary way of developing Mbed applications is with the Arm Online Ide "Keil Studio Cloud" which is an online ide that uses cloud services to build and compile mbed applications. Applications can be developed also with other development environments such as Keil μVision, IAR Embedded Workbench, Arduino IDE and Eclipse with GCC ARM Embedded tools.

Mbed OS provides the Mbed C/C++ software platform and tools for creating microcontroller firmware that runs on IoT devices. It consists of the core libraries that provide the microcontroller peripheral drivers, networking, RTOS and runtime environment, build tools and test and debug scripts. These connections can be secured by compatible SSL/TLS libraries such as Mbed TLS or wolfSSL, which supports mbed-rtos.

A components database provides driver libraries for components and services that can be connected to the microcontrollers to build a final product.

Mbed OS, the RTOS, is based on Keil RTX5.

There are various hardware demo-boards for the Mbed platform, with the first being the original Mbed Microcontroller board. The Mbed Microcontroller Board (marketed as the "mbed NXP LPC1768") is a demo-board based on an NXP microcontroller, which has an ARM Cortex M3 core, running at 96 MHz, with 512 KB flash, 32 KB RAM, as well as several interfaces including Ethernet, USB Device, CAN, SPI, I2C and other I/O. The Mbed microcontroller received first prize in the annual EDN Innovation Awards' Software/Embedded Tools category in 2010.