Onion Search Engine is a specialized tool designed for users seeking content on the Tor network, also known as the deep web or dark web. This Firefox extension ensures user privacy by eliminating cookies, JavaScript, and external code, allowing for a secure browsing experience. It not only facilitates searches within the onion network but also across the standard internet, making it versatile for various online inquiries.

With a subscription-based model, users can set the Onion Search Engine as their default search engine in Firefox. By simply entering the word 'onion' followed by a keyword, users can initiate direct searches on the onion network. This functionality is particularly useful for those who require anonymous browsing, as it emphasizes user privacy and security while accessing hidden web content.