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Bluesky API: Posting Reference

Bluesky is supported via the AT Protocol. OmniSocials posts to the specific account that completed OAuth. Both bsky.social and self-hosted PDS accounts work.

Channel ID: bluesky

Supported content types

Type	Supported
Feed post	✅
Story	-
Reel	-

Minimal example

Code
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.

Code
{
  "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 (max 4 images per part).
• Links, @mentions, and #hashtags are auto-detected and made clickable via AT Protocol rich-text facets; no manual markup needed.

Media requirements

Media	Requirement
Image	JPEG, PNG, or WebP. Max 2 MB per image after compression (see below). Up to 4 per post.
Video	MP4, up to 3 minutes, max 100 MB

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.

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.