4 releases (2 breaking)

0.2.1 Oct 31, 2023
0.2.0 Oct 18, 2023
0.1.0 Jun 29, 2023
0.0.0 Oct 20, 2021

#1077 in Embedded development

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455 downloads per month
Used in 2 crates


6.5K SLoC


embassy-net is a no-std no-alloc async network stack, designed for embedded systems.

It builds on smoltcp. It provides a higher-level and more opinionated API. It glues together the components provided by smoltcp, handling the low-level details with defaults and memory management designed to work well for embedded systems, aiiming for a more "Just Works" experience.


  • IPv4, IPv6
  • Ethernet and bare-IP mediums.
  • TCP sockets implement the embedded-io async traits.

See the smoltcp README for a detailed list of implemented and unimplemented features of the network protocols.

Hardware support

  • esp-wifi for WiFi support on bare-metal ESP32 chips. Maintained by Espressif.
  • cyw43 for WiFi on CYW43xx chips, used in the Raspberry Pi Pico W
  • embassy-usb for Ethernet-over-USB (CDC NCM) support.
  • embassy-stm32 for the builtin Ethernet MAC in all STM32 chips (STM32F1, STM32F2, STM32F4, STM32F7, STM32H7, STM32H5).
  • embassy-net-wiznet for Wiznet SPI Ethernet MAC+PHY chips (W5100S, W5500)
  • embassy-net-esp-hosted for using ESP32 chips with the esp-hosted firmware as WiFi adapters for another non-ESP32 MCU.


  • For usage with Embassy HALs and network chip drivers, search here for eth or wifi.
  • The esp-wifi repo has examples for use on bare-metal ESP32 chips.
  • For usage on std platforms, see the std examples

Adding support for new hardware

To add embassy-net support for new hardware (i.e. a new Ethernet or WiFi chip, or an Ethernet/WiFi MCU peripheral), you have to implement the embassy-net-driver traits.

Alternatively, embassy-net-driver-channel provides a higer-level API to construct a driver that processes packets in its own background task and communicates with the embassy-net task via packet queues for RX and TX.

Drivers should depend only on embassy-net-driver or embassy-net-driver-channel. Never on the main embassy-net crate. This allows existing drivers to continue working for newer embassy-net major versions, without needing an update, if the driver trait has not had breaking changes.


This crate can run on any executor.

embassy-time is used for timekeeping and timeouts. You must link an embassy-time driver in your project to use this crate.


This work is licensed under either of

at your option.


~94K SLoC