In Multilogin, you can install browser extensions through Postman by passing the local extension path in the load-extension command flag when you create or update a browser profile. Mimic uses an extracted Chrome extension folder that contains manifest.json, while legacy Stealthfox uses a Firefox .xpi file.

➡️ In Postman, open “Profile Create” or “Profile Update” → “Body” → add cmd_params under parameters → fingerprint → set "flag": "load-extension" → add the extension path as the value → click “Send”.

To load several extensions at once, add their paths as comma-separated values in the same value field.

Set up for Mimic browser

How to prepare the file

Option 1: get from Chrome

1. Visit Chrome Web Store and install an extension of your choice
2. Go to chrome://version/ and check the “Profile path”, for example:
   /Users/username/mlx/profiles/46f57e7c-b80a-371e-9a1e-568cb2830359/391670f2-9c19-4279-9a3b-5a9fcc1f1793/065a29da-a68a-4c56-bf33-3d5019abfe60/Default
3. Open this path in your file explorer and go to the Extensions folder, where you will see a folder named with an extension ID
4. Once you open it, you'll see a folder named with an extension version – this is the one that you'll need further (see “Using the file”)

 

 

How to use the file

1. Use the endpoint Profile Create or Profile Update
2. Add the following command-line argument into the fingerprint parameter

"cmd_params": {
               "params": [
                   {
                       "flag": "load-extension",
                       "value": "path-to-extension"
                   }
               ]
           }

3. Replace path-to-extension with a path to a folder created in step 4 above

Example

Here is an example of a Profile Create endpoint that installs an extension. To test it, replace the following parameters with your values:

• "folder-id"
• "C:\\Users\\Username\\Downloads\\Extension-folder-name"

{
    "browser_type": "mimic",
    "folder_id": "folder-id",
    "name": "profile-name",
    "os_type": "windows",
    "core_version": 125,
    "parameters": {
        "flags": {
            "audio_masking": "mask",
            "fonts_masking": "natural",
            "geolocation_masking": "natural",
            "geolocation_popup": "block",
            "graphics_masking": "natural",
            "graphics_noise": "natural",
            "localization_masking": "mask",
            "media_devices_masking": "custom",
            "navigator_masking": "custom",
            "ports_masking": "natural",
            "proxy_masking": "disabled",
            "screen_masking": "natural",
            "timezone_masking": "mask",
            "webrtc_masking": "mask"
        },
        "fingerprint": {
            "navigator": {
                "user_agent": "Mozilla/5.0 (Windows NT 11.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.5790.110 Safari/537.36",
                "hardware_concurrency": 4,
                "os_cpu": "windows",
                "platform": "Win32"
            },
            "media_devices": {
                "video_inputs": 1,
                "audio_inputs": 2,
                "audio_outputs": 4
            },
            "cmd_params": {
                "params": [
                    {
                        "flag": "load-extension",
                        "value": "C:\\Users\\Username\\Downloads\\Extension-folder-name"
                    }
                ]
            }
        },
        "storage": {
            "is_local": true,
            "save_service_worker": true
        }
    }
}

Set up for Stealthfox browser

How to prepare the file

1. Visit Firefox Add-ons
2. Choose your extension and right-click the “Add to Firefox” button, then choose “Save Link As”
3. An .xpi file will be downloaded to your computer

How to use the file

1. Use the endpoint Profile Create or Profile Update
2. Add the following command-line argument into the fingerprint parameter

"cmd_params": {
               "params": [
                   {
                       "flag": "load-extension",
                       "value": "path-to-extension"
                   }
               ]
           }

3. Replace path-to-extension with a path to a file downloaded in step 3 above

Example

Here is an example of a Profile Create endpoint that installs an extension. To test it, replace the following parameters with your values:

• "folder-id"
• "C:\\Users\\Username\\Downloads\\Extension-file-name"

{
    "browser_type": "stealthfox",
    "folder_id": "folder-id",
    "name": "profile-name",
    "os_type": "windows",
    "core_version": 126,
    "parameters": {
        "flags": {
            "audio_masking": "mask",
            "fonts_masking": "natural",
            "geolocation_masking": "mask",
            "geolocation_popup": "block",
            "graphics_masking": "natural",
            "graphics_noise": "natural",
            "localization_masking": "mask",
            "media_devices_masking": "custom",
            "navigator_masking": "custom",
            "ports_masking": "natural",
            "proxy_masking": "disabled",
            "screen_masking": "natural",
            "timezone_masking": "mask",
            "webrtc_masking": "mask"
        },
        "fingerprint": {
            "navigator": {
                "user_agent": "Mozilla/5.0 (Windows NT 11.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.5790.110 Safari/537.36",
                "hardware_concurrency": 4,
                "os_cpu": "windows",
                "platform": "Win32"
            },
            "media_devices": {
                "video_inputs": 1,
                "audio_inputs": 2,
                "audio_outputs": 4
            },
            "cmd_params": {
                "params": [
                    {
                        "flag": "load-extension",
                        "value": "C:\\Users\\Username\\Downloads\\Extension-file-name"
                    }
                ]
            }
        },
        "storage": {
            "is_local": true,
            "save_service_worker": true
        }
    }
}