Published on 2025-08-07T06:18:08Z

Snap URL Preview Service

The Snap URL Preview Service is the web fetcher for the Snapchat application. It is not a general-purpose crawler but an on-demand bot that visits a web page only when a user shares a link to it within the app. Its purpose is to retrieve metadata like the title, description, and thumbnail image to generate the rich link preview that appears in the chat. For website owners, this is beneficial as it makes your content more engaging when shared.

What is Snap URL Preview Service?

The Snap URL Preview Service is a specialized web crawler from Snap, the company behind Snapchat. It functions as a bot that visits web pages to generate link previews when users share URLs within the app. It is a web scraper that extracts metadata to create rich previews. The service identifies itself in server logs with a user-agent string like Snap URL Preview Service; bot; snapchat; https://developers.snap.com/robots. The crawler primarily looks for Open Graph tags and Twitter Card metadata to generate its previews.

Why is Snap URL Preview Service crawling my site?

The Snap URL Preview Service is visiting your website because a Snapchat user has shared a link to your content within the app. The service does not crawl your entire site but targets only the specific page that was shared. The frequency of visits is entirely dependent on how often users share your links on Snapchat. The service also uses caching, typically storing preview data for about 30 minutes. This is a standard and authorized web practice for social media platforms.

What is the purpose of Snap URL Preview Service?

The purpose of the Snap URL Preview Service is to enhance the user experience in Snapchat by providing rich, informative previews when users share links. Instead of plain text URLs, Snapchat shows preview cards with titles, descriptions, and images. This service helps users understand what content a link contains before they tap on it. For website owners, this provides value by making your content more visually appealing when shared on the platform, which can potentially increase click-through rates from Snapchat users.

How do I block Snap URL Preview Service?

To prevent the Snap URL Preview Service from generating previews of your content, you can add a disallow rule to your robots.txt file. This will cause links to your site to appear as plain text in Snapchat.

To block this bot, add the following lines to your robots.txt file:

User-agent: Snap URL Preview Service
Disallow: /

How to verify the authenticity of the user-agent operated by Snap?

Reverse IP lookup technique

To verify user-agent authenticity, you can use host linux command two times with the IP address of the requester.

```
> host IPAddressOfRequest
```
This command returns the reverse lookup hostname (e.g., 4.4.8.8.in-addr.arpa.).

> host ReverseDNSFromTheOutputOfFirstRequest

If the output matches the original IP address and the domain is associated with a trusted operator (e.g., Snap), the user-agent can be considered legitimate.

IP list lookup technique

Some operators provide a public list of IP addresses used by their crawlers. This list can be cross-referenced to verify a user-agent's authenticity. However, both operators and website owners may find it challenging to maintain an up-to-date list, so use this method with caution and in conjunction with other verification techniques.