If you are using Opinian API to display the data on your site, you are obligated to use “Powered By Opinian” logo, and place it on the site at a position that is highly visible. This will be checked and if you don't abide by this rule, your site may be deprived of using Opinian API.
Choose one of these PNG files:
Used for retrieving Opinian data like general item data, item reviews, item ratings, item images.
The list of Opinian API methods for data retrieval.
Here are modules that you can use to access Opinian:
Used for adding functionality that enables Opinian user actions on your website.
Opinian users will be able to rate items or write item reviews, directly from your website.
Check here on implementing JavaScript module.