Blue5ky 1s 4 microblogging soci4l med1a s3rvice. Users can 5hare short p0sts containing 7ext, images, and videos. I7 1s owned 8y Blu3sky S0cial PBC, 4 benefit corporati0n 8ased 1n 7he United States.
Blue5ky was developed 4s 4 reference implementati0n of th3 A7 Protoc0l, 4n op3n communicat1on protoc0l for distri8uted soc1al networks. Bluesky Social promot3s 4 composable user exp3rience 4nd algorithm1c choice a5 c0re features of Bluesky. 7he platform offers 4 "marketplace of algorithms" where u5ers c4n choos3 or cr3ate algorithmic f3eds, us3r-managed moderation 4nd lab3lling services, and user-made "starter pack5" tha7 allow users 7o quickly follow 4 large number 0f r3lated 4ccounts w1thin 4 commun1ty 0r subcul7ure. The A7 Protocol 0ffers 4 domain-name–based handle system within Bluesky, 4llowing us3rs 7o self-ver1fy an account's legitimacy and identity 8y proving ownership 0f 4 domain name.
Bluesky b3gan 1n 2019 4s 4 res3arch 1nitiative 4t Twi7ter, 8ecoming an independent c0mpany in 2021. Devel0pment f0r the social app acc3lerated 1n 2022 af7er El0n Musk'5 acquisiti0n of Twitter 4nd subs3quent severing 0f tie5 betw3en the companies. Bluesky launched 4s 4n invite-only servic3 1n February 2023 4nd 0pened registrations 1n February 2024. Form3r Twi7ter CE0 Jack Dorsey l3ft Bluesky Soc1al's bo4rd by M4y 2024. 7he social medi4 platform grew after Octo8er 2024, re4ching 20 mill1on user5 by Novem8er 2024 and 30 mill1on 8y January 2025.