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Host app for the WebExtension PassFF


This piece of software wraps around the zx2c4 pass shell command. It has to be installed for the PassFF browser extension to work properly.


For the host application

For the install script (except Windows)

  • curl
  • sed


Linux, MacOS, * BSD

Download the latest script from our releases page and execute it. As an example, Firefox users can do this in one line like so:

$ curl -sSL | bash -s -- firefox

Users of other supported browsers need to replace the last argument (firefox) by chrome, opera, chromium or vivaldi. The script will download the host application (a small python script) and the add-on's manifest file (a JSON config file) and put them in the right place. If you're concerned about executing a script that downloads files from the web, you can download the files yourself and run the script with the --local option instead or link the files yourself. Details below.


Download the install_host_app.bat script from our releases page and execute it from within a shell with a correct PATH, mentioning your browser in the last argument (i.e., replace firefox by chrome, opera, chromium or vivaldi if necessary). The rule of thumb is: if you can execute pass and python from your shell, then your host application will be installed correctly.

> install_host_app.bat firefox

Note: Older Windows versions might require powershell to be installed manually as the install script uses powershell internally. Windows 10 users should be fine out of the box.

Latest from GitHub

This is not recommended! Only for developers and for testing purposes!

Clone the repository. Then, run the following command.

$ make [VERSION=testing|...] [BROWSER=firefox|chrome|opera|chromium|vivaldi] install

This will generate the host application and installation scripts for the given VERSION (testing by default), and copy the host application and manifest files to the right place for your BROWSER (firefox by default).

This uses the --local option of the script, which instructs it to use the files on disk rather than downloading them from GitHub.

If this doesn't work, you can link the files yourself. First, change the path value in the passff.json file to be the absolute path to the project's bin/testing/ file. Then symlink (or copy) the file bin/testing/passff.json to the appropriate location for your browser and OS:

  • Firefox
    • Linux
      • Per-user: ~/.mozilla/native-messaging-hosts/passff.json
      • System-wide: /usr/{lib,lib64,share}/mozilla/native-messaging-hosts/passff.json
    • OS X
      • Per-user: ~/Library/Application Support/Mozilla/NativeMessagingHosts/passff.json
      • System-wide: /Library/Application Support/Mozilla/NativeMessagingHosts/passff.json
    • Windows
      • Per-user: Path contained in registry key HKEY_CURRENT_USER\Software\Mozilla\NativeMessagingHosts\passff
      • System-wide: Path contained in registry key HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\NativeMessagingHosts\passff
  • Chrome
    • Linux
      • Per-user: ~/.config/google-chrome/NativeMessagingHosts/passff.json
      • System-wide: /etc/opt/chrome/native-messaging-hosts/passff.json
    • OS X
      • Per-user: ~/Library/Application Support/Google/Chrome/NativeMessagingHosts/passff.json
      • System-wide: /Library/Google/Chrome/NativeMessagingHosts/passff.json
    • Windows
      • Per-user: HKEY_CURRENT_USER\SOFTWARE\Google\Chrome\NativeMessagingHosts\passff
      • System-wide: HKEY_LOCAL_MACHINE\SOFTWARE\Google\Chrome\NativeMessagingHosts\passff
  • Chromium
    • Linux
      • Per-user: ~/.config/chromium/NativeMessagingHosts/passff.json
      • System-wide: /etc/chromium/native-messaging-hosts/passff.json
    • OS X
      • Per-user: ~/Library/Application Support/Chromium/NativeMessagingHosts/passff.json
      • System-wide: /Library/Application Support/Chromium/NativeMessagingHosts/passff.json
  • Opera
    • Same as Chrome
  • Vivaldi
    • Linux
      • Per-user: ~/.config/vivaldi/NativeMessagingHosts/passff.json
      • System-wide: /etc/vivaldi/native-messaging-hosts/passff.json
    • OS X
      • Per-user: ~/Library/Application Support/Vivaldi/NativeMessagingHosts/passff.json
      • System-wide: /Library/Application Support/Vivaldi/NativeMessagingHosts/passff.json


Script execution failed

Connection to the host app failed or returned an unexpected result

Connection to the host app failed or returned an unexpected result! Make sure you have the latest version of the PassFF host app installed by following the installation instructions on GitHub.

Script execution failed.

You get one of these error messages? Follow the instructions below!

Remove old installations

Inappropriate installations can override another one that could work. So, it is simpler to remove everything and restart from scratch.

  • Delete any file passff.json in the folders native-messaging-hosts and NativeMessagingHosts
    • For the complete paths of these folders for your OS and browser, see the section above.
  • Verify all passff.json are deleted by doing a search.
    • Use your best file searching tool. For example: find / -type f -name 'passff.json'
Reinstall the host application

See the section above.

Check that the host application is correctly installed
  • Make sure the file is executable
    • ls -l /path/to/
  • Open passff.json and verify path is set to the absolute path of the host executable for example "path": "/path/to/"

PassFF's host application is not working and takes 99% CPU

Set a correct PATH in the script

When the PATH variable is not set correctly, pass will complain about not finding getopt and then loop forever. You can reproduce this behavior on the command line:

PATH="$(which bash | xargs dirname)" $(which pass)

Advanced Troubleshooting

If nothing above has worked out your issue...

Gather information in the web browser

In the preferences of PassFF, you can enable the status bar and debug logs in the Web Console (to open the console: Ctrl+Shift+K in Firefox, Ctrl+Shift+J in Chrome/Chromium). Enable the debugging mode in about:debugging, and reload the app.

Make sure the version of the host application is supported by PassFF

  • Open the file to find its version number
    • head /path/to/

Check the output of the host app

  • Run echo -e "\x02\x00\x00\x00[]" | /path/to/ | tail -c +4; echo
  • The typical output for an empty store is:
    • {"stderr": "", "version": "1.0.1", "exitCode": 0, "stdout": "Password Store\n"}

Testing OTP support

$ echo -e "\x19\x00\x00\x00[\"otp\",\"/www/\"]" | /path/to/ | tail -c +4; echo
{"exitCode": 0, "stderr": "", "stdout": "123456\n", "version": "1.0.1"}


If you use a customized pass installation: environment variables, customized repository path or extensions, you may have to customize the preferences section in

By modifying the preferences section in, you will be able to set:

  • COMMAND: the path to the pass script,
  • COMMAND_ARGS: additional command line arguments that are passed to pass,
  • COMMAND_ENV: additional environment variables,
  • CHARSET: the shell stdout charset.