Onion services (formerly known as “hidden services”) are services (like websites) that are only accessible through the Tor network.
Onion services offer several advantages over ordinary services on the non-private web:
An onion services’s location and IP address are hidden, making it difficult for adversaries to censor it or identify its operators.
All traffic between Tor users and onion services is end-to-end encrypted, so you do not need to worry about connecting over HTTPS.
The address of an onion service is automatically generated, so the operators do not need to purchase a domain name; the .onion URL also helps Tor ensure that it is connecting to the right location and that the connection is not being tampered with.
Just like any other website, you will need to know the address of an onion service in order to connect to it. An onion address is a string of sixteen mostly random letters and numbers, followed by “.onion”.
If you cannot reach the onion service you require, make sure that you have entered the 16-character onion address correctly: even a small mistake will stop Tor Browser from being able to reach the site.
If you are still unable to connect to the onion service, please try again later. There may be a temporary connection issue, or the site operators may have allowed it to go offline without warning.
You can also ensure that you're able to access other onion services by connecting to DuckDuckGo's Onion Service