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Bluesky API: posting reference

Bluesky is supported via the AT Protocol. OmniSocials posts to the specific account that completed OAuth: you enter your handle and sign in on Bluesky, with no app password to create. Both bsky.social and self-hosted PDS accounts work, and so do custom-domain handles.

For an overview and use cases, see Bluesky API.

Channel ID: bluesky

Supported content types

Type	Supported
Feed post	✅
Story	-
Reel	-

Minimal example

Terminal
curl -X POST https://api.omnisocials.com/v1/posts/create \
  -H "Authorization: Bearer $OMNISOCIALS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "content": { "default": "Skeeting from the API 🦋" },
    "accounts": ["your-bluesky-account-id"]
  }'

Platform-specific options

Field	Type	Description
bluesky.thread_parts	array	Publish as a chained thread instead of a single post. See Posting threads.

Posting threads

To publish a thread (a reply chain), pass bluesky.thread_parts. Each part becomes its own post, chained as a reply to the previous one.

JSON
{
  "accounts": ["your-bluesky-account-id"],
  "content": { "default": "" },
  "bluesky": {
    "thread_parts": [
      { "text": "1/3: kicking off a thread on the AT Protocol 🦋" },
      { "text": "2/3: every post is a record you own" },
      { "text": "3/3: portable identity is the whole point" }
    ]
  }
}

Rules:

• 2 to 25 parts. For a single post, omit thread_parts and use content.bluesky (or content.default) instead.
• Each text is required, non-empty, and ≤ 300 graphemes. Parts that exceed the limit are rejected with a 400.
• media_urls is optional per part: one video or up to 10 images per part (5 or more post as a gallery). A part without media gets its own link card when its text has a link.
• Links, @mentions, and #hashtags are auto-detected and made clickable via AT Protocol rich-text facets; no manual markup needed.

Link cards

A post with a link in its text and no media gets a link card for the first link, built from the page's Open Graph data: title, description and the page's Open Graph image as the thumbnail. You don't need to pass anything extra. A post with media shows the media instead of a card. A page without Open Graph data gets no card, and a card that can't be built never fails the post.

Media requirements

Media	Requirement
Image	JPEG, PNG, or WebP. Max 2 MB per image after compression (see below). Up to 10 per post: 1 to 4 post as an image grid, 5 to 10 as a gallery.
Video	MP4 or MOV, up to 10 minutes, max 300 MB. One per post.

Bluesky's servers reject image blobs over 2 MB. You do not need to pre-compress: OmniSocials automatically compresses oversized images down to fit the 2 MB cap at upload time, so you can pass images up to 10 MB and let the API handle it.

Video uploads need a verified email address on the Bluesky account (bsky.app, Settings, Account), and Bluesky sets a daily video upload limit per account. Images keep their real aspect ratio in the post.

Bluesky does not support mixing images and video in the same post: attach images only, or a single video. Mixed media returns a 400 validation_error at create/schedule time.

Alt text. Bluesky renders per-image alt text natively. Pass it by using an object entry instead of a bare string: { "url": "https://example.com/bike.jpg", "alt": "A red bicycle leaning against a brick wall" } in media_urls (or { "id": "...", "alt": "..." } in media_ids, including per-part thread media; max 1500 characters). It is sent as the image/video embed's alt.

Character limit

Bluesky enforces a 300 grapheme limit per post (emoji count as 1 grapheme, not their UTF-8 byte length). OmniSocials counts graphemes correctly when validating.

Limitations

• Links, mentions, and hashtags are made clickable automatically (via rich-text facets); you do not need to add any markup
• Bluesky does not expose post scheduling as a first-class concept. Scheduled OmniSocials posts are held on our side and published at the scheduled time.
• Polls are not supported on Bluesky
• Bluesky replies and mentions are not part of the Social Inbox