Posting Studio is a private tool that its operator runs on their own server to publish videos to the YouTube, TikTok and Instagram accounts they own, and to read back how those videos performed.
This is not a public service. There is no sign-up, no shared accounts and no way for a third party to obtain access. One installation serves one operator, who connects only accounts they themselves own and control.
Access tokens issued by the platforms are stored encrypted and are used only to publish the operator's own content and to read statistics for it. No data about other people is collected, bought or sold. Details are in the privacy policy, and any stored data can be removed on request.