While the functionality is more limited, you can actually use Monto reviews app outside of Webflow in some circumstances. This can be useful if you're embedding reviews in a 3rd party cart plugin or on outside landing pages, etc.
Note: This use case still requires also having a Webflow site in order to function
Here is what you'll need to make this work...
Step 1: Connect your Webflow site to Monto
The reviews app will still need something to reference for the reviews. This can be your Webflow site itself, your Webflow products or CMS items, or collections.
Signup for a Monto account, authorize Monto to connect to your Webflow site, and insert the global site tag in your Webflow site head code.
Step 2: Generate the Monto review widget script
You can generate a review widget here: https://www.monto.io/setup?app=reviews
Note: You can not use "Default: The current page's product or CMS item" option on 3rd party sites. The reviews widget will not appear on the site as it cannot detect the correct product/CMS slug to review.
You must use one of the other options to review such as: a collection, entire store, a specific product, or all reviews.
Step 3: Insert the Monto review widget script where you want it displayed
On the 3rd party site, paste the Monto review widget script where you want the reviews to be displayed.