How can the Rich Results Test compare mobile and desktop markup?

Definition: The Rich Results Test user-agent selector runs the same URL or code with a smartphone or desktop test identity. Each run reports the selected crawl type and provides rendered source code, so you can inspect the two outputs separately.

Key facts

• Google's Rich Results Test help places the smartphone and desktop choices below the URL or code entry box, with smartphone as the default.
• The test accepts a full page URL, and all resources needed by that page must be available to an anonymous user on the internet.
• A code test accepts an arbitrary snippet, which you can edit and run again from the tool.
• The result includes Crawled as, which identifies the crawl as smartphone or desktop, and the code explorer uses rendered source code.
• Google's common crawler reference gives separate desktop and mobile Google-InspectionTool user-agent strings for Search testing tools.

What does the smartphone or desktop choice change?

The selector chooses the user agent used while the Rich Results Test accesses the page. Google's help describes the two choices as testing a page with a smartphone or a desktop computer, and says the selector appears below the URL or code entry textbox. The same page identifies smartphone as the default user agent.

For a URL test, the page and its required resources must be reachable by an anonymous user. A firewall or password can keep a resource unavailable to the test. For a code test, the tool accepts an arbitrary snippet and lets you modify it before running it again.

Which HTTP user-agent strings are used?

Google's crawler reference names the crawler Google-InspectionTool. It lists these request strings under the desktop and mobile agents:

Desktop agent
Mozilla/5.0 (compatible; Google-InspectionTool/1.0)

Mobile agent
Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/W.X.Y.Z Mobile Safari/537.36 (compatible; Google-InspectionTool/1.0)

The same reference names Google-InspectionTool as the user-agent token for the User-agent: line in robots.txt. Its example group is:

user-agent: Google-InspectionTool
allow: /archive/1Q84
disallow: /archive/

Google states that crawl preferences addressed to this token affect Search testing tools such as the Rich Result Test and URL inspection in Search Console. The reference gives the token a testing-tools scope rather than a general Google Search scope.

How can you compare the two runs?

Use the same URL or code in two runs. Select smartphone, run the test, and note the Crawled as value, detected structured data, errors, suggestions, and rendered source. Run the same input again with desktop selected and inspect the corresponding results. Google's help says the test shows the rich result types found on the page and any errors or suggestions; it also says that the code explorer uses rendered source code.

The Crawled as field is the direct label for the selected mode: Google documents that it shows whether the crawl used smartphone or desktop. A difference between the two rendered sources or detected items identifies a device-specific result in the test output.

What does the tool document about comparison?

The documentation describes selecting one user agent for a test and rerunning the input. It documents the crawl label and rendered source for inspecting each run, but it does not describe a built-in side-by-side markup diff.

Related terms

• Structured data
• JSON-LD
• Rendered DOM
• JavaScript rendering and AI crawlers

FAQ

Which device does the Rich Results Test use by default?

Google's help says the default user agent is smartphone. You can choose desktop from the same selector below the URL or code entry box.

Does the selector use a different robots.txt token for mobile?

Google's crawler reference gives Google-InspectionTool as the robots.txt user-agent token and lists separate HTTP strings for desktop and mobile. The token is the same in the documented example.

Can I compare a code snippet as well as a URL?

Yes. The help page supports an arbitrary code snippet, and it says you can modify the snippet and run the test again. Use the same snippet for both selected user agents.

Sources

1. Google Search Console Help, "Rich Results Test", 15 October 2026
2. Google for Developers, "Google's common crawlers", 15 October 2026

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