PostEverywhere Bluesky API Guide

PostEverywhere API reference for Bluesky: request fields, media rules and examples for text posts, images, video and threads.

Publish text posts, image posts, video posts, and threads to Bluesky (the AT Protocol network). PostEverywhere handles the AT Protocol session, rich-text facets, and media attachments through a single call. For a general overview of all supported platforms, see the Introduction.

Connect your Bluesky account to PostEverywhere

Bluesky uses an app password, not OAuth. In your PostEverywhere dashboard, go to Accounts → Connect Bluesky and enter:

Your handle (e.g. yourname.bsky.social, or a custom domain handle)
An app password created at bsky.app → Settings → App Passwords (format xxxx-xxxx-xxxx-xxxx)

Use an app password, never your main account password. You can revoke it from Bluesky at any time without affecting your login.

What you can post to Bluesky

Content Type	Media Required	Description
Text post	None	Plain text post, up to 300 characters. A text post with a link gets a link card.
Image post	Image(s)	Post with up to 4 attached images.
Video post	Video (MP4)	Post with a single video attachment.
Thread	None / media	A chain of connected posts (each up to 300 characters).

Bluesky is short-form: posts are capped at 300 characters. Links, @mentions, and #hashtags in your text are detected automatically and turned into rich-text facets: you don't need to format them. URLs become clickable link facets. A text post (no images or video) that contains a link also gets a link card for the first link, built from the page's title, description and image. If the card cannot be built, the post goes out without it.

Bluesky-specific options in the API

Set these in platform_content.bluesky.settings:

Setting	Type	Default	Description
`replyControl`	string	`"everybody"`	Who can reply: `"everybody"`, `"following"`, `"mentioned"` or `"nobody"`. If Bluesky does not apply it, the post still goes out and carries a `bluesky_reply_control_not_applied` warning, shown on the post and in the `warnings` array of `GET /v1/posts/:id/results`.

Bluesky limits: characters, media and video

Requirement	Limit
Post text length	300 characters (Unicode grapheme-aware). Longer is refused with `400 content_too_long`.
Images per post	Up to 4
Image formats	JPEG, PNG, WebP (GIF and HEIC are accepted but re-encoded as a static JPEG)
Image handling	Automatically recompressed to ≤ 2 MB per image if needed
Video format	MP4 (H.264)
Video max file size	100 MB
Video duration	Up to 3 minutes
Links	Auto-detected and made clickable; a text post with a link gets a link card for the first link
Mentions / hashtags	Auto-detected from `@handle` / `#tag` in text
Thread length	Up to 25 parts in `thread_posts`, after `content`

Publish to Bluesky: a working request

Schedule a Bluesky Text Post

curl -X POST https://app.posteverywhere.ai/api/v1/posts \
  -H "Authorization: Bearer $POSTEVERYWHERE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "content": "Cross-posting from PostEverywhere: links like https://posteverywhere.ai and #hashtags are detected automatically.",
    "account_ids": [2295],
    "scheduled_for": "2026-06-01T12:00:00Z",
    "timezone": "UTC"
  }'

Schedule a Bluesky Post with Images

Upload your images first (see Upload Media), then attach the returned IDs:

curl -X POST https://app.posteverywhere.ai/api/v1/posts \
  -H "Authorization: Bearer $POSTEVERYWHERE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "content": "Four shots from launch day 🦋",
    "account_ids": [2295],
    "media_ids": [
      "11111111-1111-1111-1111-111111111111",
      "22222222-2222-2222-2222-222222222222",
      "33333333-3333-3333-3333-333333333333",
      "44444444-4444-4444-4444-444444444444"
    ]
  }'

Post a Thread

Use thread_posts to publish a connected chain. content is the first post, and each string in thread_posts becomes a reply to the one before it. You can add up to 25 parts, each up to 300 characters; a part that is too long is rejected with 400 invalid_thread_posts before anything is posted. Attached media goes on the first post only:

curl -X POST https://app.posteverywhere.ai/api/v1/posts \
  -H "Authorization: Bearer $POSTEVERYWHERE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "content": "A short thread on why we built a unified posting API 🧵",
    "account_ids": [2295],
    "thread_posts": [
      "1/ Managing every social platform by hand does not scale.",
      "2/ One API call fans out to all of them, with per-platform overrides.",
      "3/ Bluesky is one of them. Try it: https://posteverywhere.ai"
    ]
  }'

Getting better results on Bluesky

Keep it under 300 characters. Bluesky counts by Unicode grapheme, so emoji and combined characters count as one. If you need more room, use a thread.
Don't pre-shorten links or build markdown. Link, @mention and #hashtag facets are generated automatically from the raw text: paste the URL or handle directly.
Images are recompressed for you. Each uploaded image blob is capped at 2 MB; PostEverywhere downsizes large images automatically so you can send full-resolution files.

Common questions about posting to Bluesky

How do I connect a Bluesky account?

Bluesky uses an app password rather than OAuth. Create one at bsky.app → Settings → App Passwords, then add your handle and that app password under Accounts → Connect Bluesky in the PostEverywhere dashboard.

What is the character limit for Bluesky posts?

300 characters, counted by Unicode grapheme. Emoji and combined characters count as a single character. For longer content, split it across a thread using thread_posts.

Can I attach images or video to a Bluesky post?

Yes. Upload your media and pass the returned UUIDs in media_ids. Bluesky supports up to 4 images (JPEG, PNG or WebP; GIFs are converted to a static JPEG) or a single MP4 video up to 100 MB and 3 minutes. Large images are automatically recompressed to fit Bluesky's per-blob size limit.

Do links and mentions need special formatting?

No. Include the raw URL, @handle, or #hashtag in your content and PostEverywhere generates the correct AT Protocol rich-text facets automatically. Links are clickable, and on a text post without images or video the first link also gets a link card.

Can I edit a Bluesky post after it's published?

No. The AT Protocol does not expose a post-edit operation: Bluesky's official model is delete-and-repost. PATCH /v1/posts/:id only accepts posts in scheduled or draft status. To change a published Bluesky post, delete it (in the Bluesky app or via repository tooling) and recreate it from PostEverywhere.

Other platforms you can publish to

X (Twitter): similar short-form text and threading model
Threads: short-form conversational posts by Meta
LinkedIn: longer-form posts with PDF/document support

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