洋葱服务允许人们匿名的访问和发表信息，包括架设匿名网站。
洋葱服务还被依赖于提供一系列的服务：去元数据式的聊天，文件共享，利用诸如SecureDrop 或洋葱共享 进行的记者之间的互动和资源共享，更安全的软件升级，和更安全的访问如 Facebook 这样网页的渠道。
These services use the special-use top level domain (TLD) .onion (instead of .com, .net, .org, etc.) and are only accessible through the Tor network.
When accessing a website that uses an onion service, Tor Browser will show at the URL bar an icon of an onion displaying the state of your connection: secure and using an onion service.
To learn more about onion services, read How do Onion Services work?