Official Introduction Site: https://joinmastodon.org/
Source Code: https://github.com/mastodon/mastodon
Some existing mirrors, you just need to register and then log in,simply like twitter:
https://mastodon.social/ (basically official)
Accessable in Mainland China:
acg.mn (Not accept public registration)
https://m.cmx.im/ (Blocked)
It’s Mirror: https://cmx-im.work/ Mirror: https://unblockcmx.netlify.app/
mstdn.jp (japan)
markdown backup: