Set up and start the Fuchsia emulator (FEMU)

This document describes how to set up and run the Fuchsia emulator (FEMU), including networking and GPU support setup.


To run FEMU, you must have:

Building Fuchsia for FEMU

Before you can use FEMU, you need to build Fuchsia using fx set, specifying a qemu board and supported product. This example uses qemu-x64 for the board and workstation for the product:

Note: More information on supported boards and products is in the Fuchsia emulator overview.

Configure network

For Fuchsia's ephemeral software to work with FEMU, you need to configure an IPv6 network.


To enable networking in FEMU using tap networking, run the following commands:


User Networking (SLIRP){: .external} is the default networking set up for FEMU on macOS. This networking set up does not support Fuchsia device discovery.

Start FEMU

The most common way to run FEMU is with networking enabled, using the following commands.


To support device discovery without access to external networks.

fx vdl start -N

To get access to external networks:

{% dynamic if user.is_googler %}

Note: Command will differ depending on the type of machines you use.

  • {Corp}

    To use FEMU on a corp machine, see go/fuchsia-emulator-corp.

  • {Non-Corp}

    Note: FUCHSIA_ROOT is the path to the Fuchsia checkout on your local machine (ex: ~/fuchsia).

    fx vdl start -N -u {{ '<var>' }}FUCHSIA_ROOT{{ '</var>' }}/scripts/

{% dynamic else %}

Note: FUCHSIA_ROOT is the path to the Fuchsia checkout on your local machine (ex: ~/fuchsia).

fx vdl start -N -u {{ '<var>' }}FUCHSIA_ROOT{{ '</var>' }}/scripts/

{% dynamic endif %}

Once you run the command, a separate window opens with the title “Fuchsia Emulator”. After the Fuchsia emulator launches successfully, the terminal starts with the SSH console. You can run shell commands in this window, just like you would on a Fuchsia device.


On macOS, Fuchsia device discovery does not work. However, you can still use fx tools such as fx ssh.

fx vdl start

From the output, take note of the instruction on running fx set-device, you will need it for the steps below.

Note: When you launch FEMU for the first time on your Mac machine after starting up (ex: after a reboot), a window pops up asking if you want to allow the process “aemu” to run on your machine. Click “allow”.

Run fx set-device to specify the launched Fuchsia emulator SSH port. For SSH_PORT, use the value that the fx vdl start --host-gpu command outputted.

fx set-device{{ '<var>' }}SSH_PORT{{ '</var>' }}

Additional FEMU options

Input options

By default FEMU uses multi-touch input. You can add the argument --pointing-device mouse for mouse cursor input instead.

fx vdl start --pointing-device mouse

Run FEMU without GUI support

If you don't need graphics or working under the remote workflow, you can run FEMU in headless mode:

fx vdl start --headless

Specify GPU used by FEMU

By default, FEMU launcher uses software rendering using SwiftShader. To force FEMU to use a specific graphics emulation method, use the parameters --host-gpu or --software-gpu to the fx vdl start command.

These are the valid commands and options:

Supported hardware for graphics acceleration

FEMU currently supports a limited set of GPUs on macOS and Linux for hardware graphics acceleration. FEMU uses a software renderer fallback for unsupported GPUs.


To exit FEMU, run dm poweroff in the FEMU terminal.

Next steps