Bluesky is a microblogging social network built on the AT Protocol, an open system in which accounts are portable between hosting providers and users can choose their own feeds.
How Bluesky works
Bluesky started as a project inside Twitter in 2019 and became an independent company. The app opened to the public in February 2024. It looks like a familiar short-post network, but it runs on the AT Protocol, which separates where your data is stored from the app you read it in.
Features that set it apart:
- Domain handles: you can use a domain you own as your handle, which doubles as verification.
- Custom feeds: anyone can build a feed algorithm, and users pick which ones to follow. The default Following feed is chronological.
- Stackable moderation: users can subscribe to independent labeling services.
- Account portability: you can move your account to another hosting provider and keep your followers.
Posting limits
- 300 graphemes per post.
- Up to 4 images, each up to about 1 MB.
- Links, mentions, and hashtags are stored as "facets" so they are clickable.
An example
A developer tools company posts a two-part thread about a release, with a screenshot and alt text. Its handle is its own domain.
Why it matters for AI-agent publishing
Bluesky's open API makes it straightforward to post to, and its audience skews toward developers and researchers. Agents must count graphemes, not characters, and must set facets or links will show as plain text.
SocialHandoff publishes Bluesky threads, up to 4 images with alt text, and clickable links, mentions, and tags. See connect Bluesky and scheduling for Bluesky, and check length with the Bluesky character counter.