Running Blimp

See build for instructions on how to build Blimp.

Android Client

Installing the client

Install the Chrome Public APK with the following:

./build/android/ $(PRODUCT_DIR)/apks/ChromePublic.apk

This is mostly equivalent to just running:

adb install $(PRODUCT_DIR)/apks/ChromePublic.apk

Setting up command line flags

Set up any command line flags with:

./build/android/adb_chrome_public_command_line --your-flag-here

To see your current command line, run adb_blimp_command_line without any arguments.

The Chrome APK blimp client reads command line arguments from the file /data/local/chrome-command-line and the above script reads/writes that file. Typical format of the file is chrome --your-flag-here. So one can use adb directly to create the file:

echo 'chrome --engine-ip= --engine-port=25467 --engine-transport=tcp' \
  '--blimp-client-token-path=/data/data/' \
  '--vmodule="*=1""' > /tmp/chrome-command-line
adb push /tmp/chrome-command-line /data/local/chrome-command-line
adb shell start chmod 0664 /data/local/chrome-command-line

Forcefully enabling the blimp client

Usually, the end user will have to manually enable blimp by using the Blimp panel in the application settings, but for developers it might be beneficial to skip this check by forcefully enabling the blimp client.

You can do this by adding the command line flag:


Note: This still does not skip the authentication checks for the assigner. You will still have to either pass in the --engine-ip=... argument or sign in with a valid account.

Instructing client to connect to specific host

To have the client connect to a custom engine use the --engine-ip, --engine-port, and --engine-transport flags. The possible valid values for --engine-transport are ‘tcp’ and ‘ssl’. An example valid endpoint would be --engine-ip= --engine-port=25467 --engine-transport=tcp.

SSL-encrypted connections take an additional flag --engine-cert-path which specifies a path to a PEM-encoded certificate file (e.g. --engine-cert-path=/path_on_device_to/file.pem). Remember to also copy the file to the device when using this option.

Requesting the complete page from the engine

The engine sends partially rendered content to the client. To request the complete page from the engine, use the --download-whole-document flag on the client.

Specifying the client auth token file

The client needs access to a file containing a client auth token. One should make sure this file is available by pushing it onto the device before running the client. One can do this by running the following command:

adb push /path/to/blimp_client_token \

To have the client use the given client auth token file, use the --blimp-client-token-path flag (e.g. --blimp-client-token-path=/data/data/

An example of a client token file is test_client_token.

Start the Client

Run the Chrome Public APK with:


The script under the cover uses adb to start the application:

adb shell am start -a android.intent.action.VIEW -n

Connecting to an Engine running on a workstation

To run the engine on a workstation and make your Android client connect to it, you need to forward a port from the Android device to the host, and also instruct the client to connect using that port on its localhost address.

Port forwarding

If you are running the engine on your workstation and are connected to the client device via USB, you'll need remote port forwarding to allow the Blimp client to talk to your computer.

Option A

Follow the remote debugging instructions to get started. You'll probably want to remap 25467 to “localhost:25467”. Note This requires the separate Chrome application to be running on the device. Otherwise you will not see the green light for the port forwarding.

Option B

If you are having issues with using the built-in Chrome port forwarding, you can also start a new shell and keep the following command running:

./build/android/ --debug -v 25467 25467

Running the client in an Android emulator

Running the client using an Android emulator is similar to running it on device. Here are a few gotchas:

  • Build an APK matching the emulator cpu type. The emulator cpu type is most likely x86, while the default Android build cpu type is ARM. Follow the Android build instructions above to change the CPU type.

  • Ensure that the emulator is running at least Android Marshmallow so that fonts are rendered correctly. Also ensure that you have the latest Play services binaries.

  • Some of scripts under build/android will fail to run as it uses adb scp. Follow the instruction above to use adb directly.

  • To connect to an Engine running on the host machine, you should use as engine-ip instead of as will refer to the emulator itself. There is no need of set up port forwarding when this approach is used.

Linux Client

The Linux client is useful for development purposes where the full Android UI is not required.

Build with the following commands:

gn gen out-linux/Client
ninja -C out-linux/Client blimp_shell

To run it with local logging enabled, execute:

./out-linux/Client/blimp_shell \
  --user-data-dir=/tmp/blimpclient \
  --enable-logging=stderr \
  --vmodule="*=1" \
  --engine-ip= \
  --engine-port=25467 \
  --engine-transport=tcp \

PS: Create the /tmp/blimpengine-token file with any sequence of characters. For example:

echo "anything" > /tmp/blimpengine-token

Running the engine

In a container

For running the engine in a container, see container.

On a workstation

The following flags are required to start an Engine instance:

  • --blimp-client-token-path=$PATH: Path to a file containing a nonempty token string. If this is not present, the engine will fail to boot.
  • --use-remote-compositing: Ensures that the renderer uses the remote compositor.
  • --disable-cached-picture-raster: Ensures that rasterized content is not destroyed before serialization.
  • --android-fonts-path=$PATH: Path to where the fonts are located. If the Android client is Kitkat system, this would be out-linux/Debug/gen/third_party/blimp_fonts/font_bundle/kitkat/. If the Android client is Marshmallow system, this would be out-linux/Debug/gen/third_party/blimp_fonts/font_bundle/marshmallow/.
  • --disable-remote-fonts: Disables downloading of custom web fonts in the renderer.

Typical invocation

One can start the engine using these flags:

out-linux/Debug/blimp_engine_app \
  --android-fonts-path=out-linux/Debug/gen/third_party/blimp_fonts/font_bundle/marshmallow/ \
  --blimp-client-token-path=/tmp/blimpengine-token \
  --enable-logging=stderr \

Running client engine integration with script

When building the target blimp on a Linux host, a script is created which automates running the Blimp client and starting the engine. Setting up the environment like this is much quicker than executing each of the steps separately. It is used for development purpose as well as running tests under integration environment.

Generate the script

The script is wrapped as an command client_engine_integration and ends up in out-linux/Debug/bin/ which is generated with building engine. Command should be with the positional argument {start,run,load,stop}.

Running the script

One can use the script to set up engine and connect it with client, then start client.

Option A

  1. {start} Start engine & forwarder:

    out-linux/Debug/bin/client_engine_integration start

    Engine runs until when you run the script with {stop} as the positional argument.

  2. After engine starting successfully, run {load} client which installs apk in device and runs blimp.

    out-linux/Debug/bin/client_engine_integration load -p/--apk-path /path/to/apk

    You are now ready to run tests or do development.

    Instead of {load}, if want to manually install/launch the client can also do e.g. the incremental install:

    ninja -C out-android/Debug blimp chrome_public_apk_incremental && \
  3. {stop} Stops the engine & the forwarder:

    out-linux/Debug/bin/client_engine_integration stop

Option B

  1. {run} Start and keep running engine & forwarder. Script keeps running and auto-checking engine process. Is responsible for killing engine if keyboard interrupts or client gets killed.

    out-linux/Debug/bin/client_engine_integration run
  2. Same as step 2 in Option A.

  3. Engine should be auto-killed by keyboard stopping the {run} script or the client gets wiped out. {stop} works as well.