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AI Discovery

What is WebSub?

Also known as: PubSubHubbub, Real-time Content Distribution, Push Protocol

WebSub (formerly PubSubHubbub) is a real-time content distribution protocol that pushes updates to subscribers instantly when you publish new content, so feed readers, aggregators and other subscribers hear about it within seconds instead of waiting for periodic crawls.

Read the full guide: llms.txt Implementation →

Understanding What is WebSub?

WebSub (W3C standard, formerly known as PubSubHubbub) is a real-time content distribution protocol that notifies subscribers instantly when you publish or update content. Instead of subscribers periodically polling your feed (which can take hours or days), WebSub pushes updates to them within seconds of publication.

How WebSub Works

The WebSub workflow involves three parties:

  • Publisher (You): Your website publishes content and announces updates
  • Hub (Middleware): A server (like Google's hub) that receives publish notifications
  • Subscriber: Feed readers, aggregators and other services that want real-time updates from your site

When you publish new content, your site pings the hub, which immediately notifies all subscribers. This is dramatically faster than waiting for crawlers to revisit your sitemap.

WebSub for AI Discoverability

In the context of LLMO (LLM Optimization), WebSub is part of the advanced infrastructure layer that maximizes AI crawler efficiency:

  • Speed: Subscribers learn about new content within seconds instead of on their next poll
  • Freshness: Your feeds stay current wherever they are syndicated
  • Efficiency: Subscribers fetch only when you notify them, instead of polling
  • Reach: Anything that reads your feed, including services that feed AI tools, gets the update fast

Implementation

To implement WebSub:

  • 1. Add Hub Link: Include <link rel="hub" href="https://pubsubhubbub.appspot.com/"> in your RSS/Atom feeds
  • 2. Ping on Publish: Send POST request to hub whenever you publish new content
  • 3. Maintain Feeds: Keep RSS/Atom feeds up-to-date (required for WebSub)

Pressonify pings a WebSub hub whenever a press release is published, as part of its AI Discovery Protocol (ADP) implementation.

WebSub vs Traditional Crawling

Comparison of discovery speeds:

  • Polling and crawling: Hours to days, depending on how often subscribers check
  • WebSub push: Seconds for subscribers to receive updates

For time-sensitive content (press releases, breaking news, product launches), WebSub gets the latest information to subscribers within seconds. This speed advantage is critical in the Citation Economy where freshness impacts citability.

Key Takeaways

  • WebSub pushes content updates to subscribers instantly (seconds vs hours)
  • Much faster than waiting for the next poll or crawl
  • Keeps syndicated feeds fresh
  • Part of advanced LLMO infrastructure for maximum AI visibility
  • Requires RSS/Atom feeds and hub ping implementation

Frequently Asked Questions

No. WebSub is an advanced optimization for time-sensitive content. Basic AI visibility requires robots.txt + llms.txt. WebSub adds real-time push capabilities.
No major AI provider documents subscribing to WebSub directly. Google runs a public hub (pubsubhubbub.appspot.com) that feed readers and aggregators use, so treat WebSub as a fast path to feed consumers rather than a direct line to AI models.

Related Terms

LLMO (LLM Optimization) (LLMO) ADP (AI Discovery Protocol) (ADP)

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