HACKER Q&A
📣 zagrebian

How does Google share my login information with YouTube?


Steps to reproduce:

1. Install Firefox 2. Go to google.com 3. Log in with your Google account 4. Go to youtube.com 5. You are already logged in

I would like to understand how Youtube receives my Google login information. I assume that logins on the web are based on websites, and since google.com and youtube.com are two different websites, Youtube should not be able to access my Google login.

So how does Youtube do it? If this were Chrome, I would assume that it’s some sort of Google integration, but this is Firefox, so there must be a standard web API at work here.

  👤 Nextgrid Accepted Answer ✓
If you look at the chain of redirects during your Google login you'll be redirected to youtube.com before redirecting back to Google.
👤 neximo64
Youtube is a part of Google, they got rid of Youtube logins and merged it to use Google accounts to login in shortly after being acquired.
👤 MattGaiser
> since google.com and youtube.com are two different websites

Both are part of Google.