What is Yahoo Link Preview?

Yahoo Link Preview is an automated web service operated by Yahoo that generates visual link previews for URLs shared within Yahoo Mail. This specialized web client fetches and analyzes web pages to extract metadata like titles, descriptions, and images when users paste links in emails. Yahoo Link Preview enhances the email composition experience by showing recipients what content they can expect before clicking.

The service identifies itself in server logs with the user agent string Mozilla/5.0 (compatible; Yahoo Link Preview; https://help.yahoo.com/kb/mail/yahoo-link-preview-SLN23615.html), which includes a helpful documentation link. In some cases, you might see additional identifiers appended to this string, such as version numbers or service identifiers.

Yahoo Link Preview uses a headless browser environment that can partially render JavaScript, though it primarily relies on static HTML analysis. It's designed for efficient metadata extraction with minimal resource consumption, focusing specifically on Open Graph tags with fallbacks to standard HTML metadata when needed.

Why is Yahoo Link Preview crawling my site?

Yahoo Link Preview visits your site when someone includes a link to your content in a Yahoo Mail message. These visits are triggered by user actions rather than systematic crawling, making them sporadic and unpredictable. Unlike search engine crawlers that methodically index content, Yahoo Link Preview only targets specific URLs that users share.

The service looks primarily for metadata that helps create rich link previews, focusing on elements like:

Page titles and descriptions
Featured images
Open Graph tags that specify how content should appear when shared
Basic site information

These visits typically happen just once per URL (unless shared again later) as Yahoo implements caching to reduce duplicate requests for popular links. The crawler operates with strict timeout handling, abandoning slow-responding pages faster than typical search crawlers.

What is the purpose of Yahoo Link Preview?

Yahoo Link Preview exists to enhance user experience in Yahoo Mail by transforming plain text URLs into visually informative previews. When someone pastes a link into an email, the preview system retrieves metadata from the target page and constructs a card layout showing a thumbnail image, title, and brief description.

This service benefits both email senders and recipients. For senders, it creates more engaging messages with higher click-through rates compared to plain text links. For recipients, the previews provide visual verification of link destinations before clicking, helping users make informed decisions about which links to follow.

Additionally, the system contributes to Yahoo's anti-phishing efforts by analyzing domain reputation as part of the preview generation process, adding a layer of security to the email experience.

How do I block Yahoo Link Preview?

If you prefer to prevent Yahoo Link Preview from generating previews of your site content, you can use standard robots.txt directives. Yahoo Link Preview respects robots.txt rules, making this the simplest approach for controlling access.

To block Yahoo Link Preview completely, add these lines to your robots.txt file:

User-agent: Yahoo Link Preview
Disallow: /

To block access to specific sections while allowing previews for other content:

User-agent: Yahoo Link Preview
Disallow: /private/
Disallow: /members/
Allow: /

Alternatively, you can optimize how your content appears in previews by implementing proper Open Graph tags in your HTML. This gives you control over which images, titles, and descriptions appear when your links are shared in Yahoo Mail.

Keep in mind that blocking Yahoo Link Preview may impact how your links appear when shared through Yahoo Mail. Instead of rich previews with images and descriptions, users will see only the plain URL, potentially reducing engagement with your content. For most public-facing websites, allowing these previews is beneficial as they can increase visibility and click-through rates.

Yahoo Link Preview