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$device_json

The $device_json variable holds a complete detection result in JSON format. It is set by the device-type module for each HTTP request, providing detailed information about the device, browser, operating system, and bot classification.

Type

JSON

Possible values

The $device_json variable contains a JSON object with detailed device detection information. Example values include:

  • For a mobile device: 

    {
  "type": "mobile",
  "browser": {"name": "Chrome", "version": "120.0", "engine": "Blink"},
  "os": {"name": "Android", "version": "14", "family": "Android"},
  "device": {"brand": "Google", "model": "Pixel 8"},
  "bot": null
}

  • For a bot: 

    {
  "type": "bot",
  "browser": {"name": "", "version": "", "engine": ""},
  "os": {"name": "", "version": "", "family": ""},
  "device": {"brand": "", "model": ""},
  "bot": {"name": "GPTBot", "category": "ai_crawler", "producer": "OpenAI", "is_ai": true}
}

Examples

Logging Device Information

To log the complete device detection result, you can include $device_json in your log_format.

http {
    log_format main '$remote_addr - $remote_user [$time_local] '
                    '"$request" $status $body_bytes_sent '
                    '"$http_referer" "$http_user_agent" '
                    '$device_json';

    access_log /var/log/nginx/access.log main;
}

Adding Device Information to Response Headers

You can add the device detection result to response headers for debugging or analytics purposes.

server {
    location / {
        add_header X-Device-Info $device_json;
        proxy_pass http://backend;
    }
}

Conditional Access Control

Use $device_json to block certain types of devices or bots based on the detection result.

server {
    location / {
        if ($device_json ~* "ai_crawler") {
            return 403 "Access denied for AI crawlers";
        }
        proxy_pass http://backend;
    }
}