PreviewerAppBot | Previewer.app

About Previewer Bot

Previewer.app currently serves two main purposes:

Website: For marketers, influencers, developers, and others who want to see how their site or page will be fetched by social platforms or various scripts.
Google Chrome Extension: Powering the Previewer.app Tooltip Chrome extension, which uses the same bot. The tooltip triggers when users hover over any http(s) link.

This bot is not a typical crawler. It doesn’t walk through the site. Instead, it has a single, focused purpose - to access the link, follow any redirects, and download just enough of the page (primarily the <head> metadata) needed for preview. The bot can be triggered either from the tooltip or directly from the website.
The bot identifies itself with this user agent: PreviewerAppBot/1.0 (+https://previewer.app).

Tooltip-triggered requests: When triggered by hovering over a link in the extension, the bot creates a cache for approximately one week. During this period, repeated hovers over the same URL do not cause additional requests - the cached data is served instead.
Proxy security: The entire extension is fully proxied, securing users’ privacy and safety - this includes favicon, images, and URLs. For example, if a site has 10 links and the user hovers over each, only one request is made per URL per week.
Data fetched: The bot downloads bytes up to and slightly beyond the </head> tag, reading the raw HTTP response carefully, without executing any JavaScript.
Gentle to target sites: Both the bot and cache system are designed to minimize load and be gentle to the targeted sites.
Direct site requests: When the request is made directly from the site (not the tooltip), the same URL can only be requested once every 30 seconds to avoid overloading.

In summary, Previewer.app’s bot is built for safety, efficiency, and privacy - helping users preview content quickly without causing undue load on sites or compromising user security.