Native manifests

Native manifests are JSON files provisioned on the user's computer by means other than the extension installation process. For example, a native manifest might be provisioned by a device administrator or native application installer.

There are three types of native manifest:

Native messaging manifests Enables a feature called native messaging, in which an extension can communicate with a native app installed on the device.
Managed storage manifests Defines read-only data that an extension can access using the storage.managed API.
PKCS #11 manifests Enables an extension to use the pkcs11 API to enumerate PKCS #11 security modules and install them in Firefox.

For all native manifests, you need to store the file so the browser can find it. The section on manifest location describes how to do this. On Linux and macOS, the files are in a fixed location, on Windows the file location is written to the Windows Registry.

Native messaging manifests

The native messaging manifest is a file with a name that matches the string passed by the extension into runtime.connectNative() or runtime.sendNativeMessage() with the .json extension. It contains a JSON object with these properties:

Name Type Description
name String

Name of the native application.

This must match the name passed into runtime.connectNative() or runtime.sendNativeMessage() by the extension.

On Windows, use this value as the name of the registry key you create that contains the location of the native messaging manifest.

The name must match the regular expression: "^\w+(\.\w+)*$". This means that it may only contain (lowercase or uppercase) alphanumeric characters, underscores, and dots. It may not start or end with a dot, and a dot cannot be followed by another dot.

description String Description of the native application.
path String

Path to the native application.

On Windows, this may be relative to the manifest itself. On MacOS and Linux, it must be absolute.

type String

Describes the method used to connect the extension with the app.

Takes the value "stdio" only, which indicates that messages are received by the app using standard input (stdin) and sent using standard output (stdout).

allowed_extensions Array of String

An array of Add-on ID values. Each value represents an extension allowed to communicate with this native application.

Note: This means you want to include the browser_specific_settings key in your extension's manifest.json file so you set an explicit ID during development.

For example, here's the content of the ping_pong.json manifest file for the ping_pong native application from the native messaging example:

json
{
  "name": "ping_pong",
  "description": "Example host for native messaging",
  "path": "/path/to/native-messaging/app/ping_pong.py",
  "type": "stdio",
  "allowed_extensions": ["ping_pong@example.org"]
}

This allows the extension with the ID ping_pong@example.org to connect by passing the name ping_pong into the relevant runtime API function. The native application is at /path/to/native-messaging/app/ping_pong.py.

Managed storage manifests

The managed storage manifest is a file with a name that matches the ID specified in the extension's browser_specific_settings key with the .json extension. It contains a JSON object with these properties:

Name Type Description
name String

The ID of the extension that can access this storage, given as the ID specified in the extension's browser_specific_settings key.

On Windows, use this as the name of the registry key you create, which contains the location of the manifest.

description String Human-readable description, ignored by Firefox.
type String

This must be "storage".
data Object

A JSON object that may contain any valid JSON values, including strings, numbers, booleans, arrays, or objects. This becomes the data in the browser.storage.managed storage area.

For example, in the favourite-colour example manage storage data is set in the file named favourite-colour-examples@mozilla.org.json, which contains:

json
{
  "name": "favourite-colour-examples@mozilla.org",
  "description": "ignored",
  "type": "storage",
  "data": {
    "color": "management thinks it should be blue!"
  }
}

The favourite-colour-examples@mozilla.org extension then accesses the data using code like this:

js
let storageItem = browser.storage.managed.get("color");
storageItem.then((res) => {
  console.log(`Managed color is: ${res.color}`);
});

PKCS #11 manifests

The PKCS #11 manifest is a file with a name that matches the name of the PKCS #11 module (as used in the pkcs11 API) with the .json extension. It contains a JSON object with these properties:

Name Type Description
name String

Name of the PKCS #11 module.

This must match the name used in the pkcs11 API.

On Windows, use this as the name of the registry key you create, which contains the location of the manifest.

The name must match the regular expression: "^\w+(\.\w+)*$". This means that it may only contain lowercase alphanumeric characters, underscores, and dots. It may not start or end with a dot, and a dot cannot be followed by another dot.

description String

Description of the PKCS #11 module.

This sets the friendly name for the module in the browser's UI (for example, the "Security Devices" dialog in Firefox).

path String

Path to the PKCS #11 module.

The path to the PKCS #11 module may be absolute or relative to the manifest itself.
type String This must be "pkcs11".
allowed_extensions Array of String

An array of Add-on ID values. Each value represents an extension allowed to interact with the module.

Note: This means you want to include the browser_specific_settings key in your extension's manifest.json file so you set an explicit ID during development.

For example:

json
{
  "name": "my_module",
  "description": "My test module",
  "type": "pkcs11",
  "path": "/path/to/libpkcs11testmodule.dylib",
  "allowed_extensions": ["my-extension@mozilla.org"]
}

Given this JSON manifest, saved as my_module.json, the my-extension@mozilla.org extension could install the security module at /path/to/libpkcs11testmodule.dylib using code like this:

js
browser.pkcs11.installModule("my_module");

Manifest location

On Linux and macOS, you need to store the manifest in a particular place. On Windows, you need to create a registry key that points to the manifest's location.

The detailed rules are the same for all the manifest types, except that the penultimate component of the path identifies the type of manifest. The examples below show the form for each of the three different types. In all the examples, <name> is the value of the name property in the manifest.

Windows

For global visibility, create a registry key with the following name:

HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\NativeMessagingHosts\<name>

HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\ManagedStorage\<name>

HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\PKCS11Modules\<name>

The key should have a single default value, which is the path to the manifest.

Warning: As of Firefox 64, the 32-bit registry view Wow6432Node will be checked first for these keys, followed by the "native" registry view. Use whichever is appropriate for your application.

For Firefox 63 and older: This key should not be created under Wow6432Node, even if the app is 32-bit. Previous versions of the browser will always look for the key under the "native" view of the registry, not the 32-bit emulation. To ensure that the key is created in the "native" view, you can pass the KEY_WOW64_64KEY or KEY_WOW64_32KEY flags into RegCreateKeyEx. See Accessing an Alternate Registry View.

For per-user visibility, create a registry key with the following name:

HKEY_CURRENT_USER\SOFTWARE\Mozilla\NativeMessagingHosts\<name>

HKEY_CURRENT_USER\SOFTWARE\Mozilla\ManagedStorage\<name>

HKEY_CURRENT_USER\SOFTWARE\Mozilla\PKCS11Modules\<name>

The key should have a single default value, which is the path to the manifest.

macOS

For global visibility, store the manifest in:

/Library/Application Support/Mozilla/NativeMessagingHosts/<name>.json

/Library/Application Support/Mozilla/ManagedStorage/<name>.json

/Library/Application Support/Mozilla/PKCS11Modules/<name>.json

For per-user visibility, store the manifest in:

~/Library/Application Support/Mozilla/NativeMessagingHosts/<name>.json

~/Library/Application Support/Mozilla/ManagedStorage/<name>.json

~/Library/Application Support/Mozilla/PKCS11Modules/<name>.json

Linux

For global visibility, store the manifest in either:

/usr/lib/mozilla/native-messaging-hosts/<name>.json

/usr/lib/mozilla/managed-storage/<name>.json

/usr/lib/mozilla/pkcs11-modules/<name>.json

or:

/usr/lib64/mozilla/native-messaging-hosts/<name>.json

/usr/lib64/mozilla/managed-storage/<name>.json

/usr/lib64/mozilla/pkcs11-modules/<name>.json

For per-user visibility, store the manifest in:

~/.mozilla/native-messaging-hosts/<name>.json

~/.mozilla/managed-storage/<name>.json

~/.mozilla/pkcs11-modules/<name>.json