The ESP8266 and ESP32 are families of microcontroller systems-on-chip made by Espressif Systems, distinguished by integrating wireless networking directly onto a cheap, single chip. Where most microcontrollers need a separate, often expensive, module to get online, these parts put a 2.4 GHz Wi-Fi radio (and, on the ESP32, Bluetooth as well) on the same die as the processor. Espressif describes the ESP32 as “a revolutionary Wi-Fi + Bluetooth SoC for IoT applications,” and the earlier ESP8266 as a “32-bit MCU and 2.4 GHz Wi-Fi” device. That integration, at a price point of only a few dollars, is the core of why these chips matter.
The ESP8266 came first and caused a stir among hobbyists because it was strikingly cheap yet capable of joining a Wi-Fi network and running user code. The ESP32 followed as a more powerful successor, described in Espressif’s documentation as “a system on a chip that integrates Wi-Fi (2.4 GHz band), Bluetooth, dual high performance Xtensa 32-bit LX6 CPU cores” and built on a 40 nm process for good power efficiency. The ESP32 adds Bluetooth Classic and Bluetooth Low Energy alongside Wi-Fi, more processing power, more memory, and a generous set of peripherals, including dozens of GPIO pins and interfaces such as SPI, I2C, UART, and I2S.
Espressif supports the chips with ESP-IDF, its official development framework, which the company documents as being for “development of Internet-of-Things (IoT) applications with Wi-Fi, Bluetooth, power management and several other system features.” Crucially for the chips’ popularity, the ecosystem extends well beyond ESP-IDF: the boards can be programmed through the Arduino IDE using an ESP32 core, and they run MicroPython, letting people write networked hardware in Python. This meant a maker already comfortable with Arduino sketches or Python could add internet connectivity to a project with almost no new tooling.
The combination of low cost, on-chip wireless, and familiar programming environments made the ESP family the default brain of countless do-it-yourself connected devices. Hobbyists built Wi-Fi-enabled sensors, smart-home gadgets, weather stations, and home-automation nodes on these chips, and they became a backbone of open-source IoT firmware projects. Inexpensive development boards built around the modules, often costing only a few dollars, brought network-connected microcontrollers within reach of anyone, much as Arduino had done for basic physical computing a decade earlier.
The historical importance of the ESP8266 and ESP32 is that they collapsed the cost and complexity of putting a microcontroller on the network. Before them, adding Wi-Fi to a small embedded project was awkward and relatively expensive; after them, it was nearly trivial. That shift is a large part of why the hobbyist and prototyping side of the Internet of Things expanded so quickly in the late 2010s, and the chips remain a staple of maker electronics and commercial connected products alike.