Crosspost to X, Bluesky and LinkedIn

Crossposting is publishing one piece of content to several networks or accounts, usually adjusted for each. For a developer it typically means one announcement going to X, Bluesky and LinkedIn at the same moment, from one place in your code.

The adjusting is where it goes wrong. Each network counts length differently, formats text differently, and rejects identical repeats on the same account. A crossposting tool's job is to make those differences visible before you publish, not after one network has posted and another has refused.

Take a 294-character release note with a 34-character link. On Bluesky it is 294 graphemes, under the 300 limit. On X it is 283 weighted characters, because the link counts as 23 but the limit is 280. On LinkedIn it is far under 3,000. One text, three answers.

Emoji and non-Latin text change the math again. Every emoji counts 2 on X and 1 on Bluesky. A Japanese sentence like 新機能: 予約投稿をAPIから取り消せるようになりました。 is 29 graphemes on Bluesky but 53 weighted characters on X, because each Japanese character counts 2 there. The X, Bluesky and LinkedIn limit pages have the full rules.

This request sends the full note to Bluesky and LinkedIn and a shorter version to X. dry_run: true means nothing is published; we only check it.

curl https://socialsforai.vercel.app/v1/posts \
  -H "Authorization: Bearer $SOCIALS_API_KEY" \
  -d '{
    "accounts": ["acc_bsky_team", "acc_linkedin_cto", "acc_x_company"],
    "text": "Release notes for v2.4 are up. Scheduled posts can now be canceled from the API, webhooks retry for 24 hours, and the Bluesky connector supports custom PDS hosts. Everything new, with request examples for curl, TypeScript and Python, is on the changelog page: https://example.com/changelog/v2-4",
    "platform_options": {
      "x": { "text": "v2.4 is out: cancel scheduled posts from the API, 24h webhook retries, custom Bluesky PDS hosts. https://example.com/changelog/v2-4" }
    },
    "dry_run": true
  }'

The preview shows the exact text each account will get (shortened here). ok is true because the X override is 120 weighted characters. The only issue is the x_link_cost warning, which doesn't block. Without the override, the issues list would contain a text_too_long error for acc_x_company: "Text is 283 characters; X allows 280.", with the fix "Shorten it by 3+ characters, or set platform_options.x.text to a shorter version."

{
  "object": "preflight",
  "ok": true,
  "issues": [
    {
      "account_id": "acc_x_company",
      "platform": "x",
      "severity": "warning",
      "code": "x_link_cost",
      "message": "Posts with a URL cost $0.200 through the X API instead of $0.015 (docs.x.com pricing).",
      "fix": "Remove the link, or send a link-free version for X in platform_options.x.text. A link in a reply is also billed at the with-URL rate."
    }
  ],
  "preview": [
    { "account_id": "acc_bsky_team", "platform": "bluesky", "text": "Release notes for v2.4 are up. ..." },
    { "account_id": "acc_linkedin_cto", "platform": "linkedin", "text": "Release notes for v2.4 are up. ..." },
    { "account_id": "acc_x_company", "platform": "x", "text": "v2.4 is out: cancel scheduled posts ..." }
  ]
}

The others still publish. Each account is a separate target with its own status, attempts and error. If all succeed, the post is published. If some succeed and others fail permanently, it's partially_published, and the post.partially_published webhook lists which target failed and why.

Retryable failures, such as a rate limit or a 5xx from one network, retry only that target after 30s, 2m, 10m, 30m and 2h. The post's final status is set once every target has finished. To resend only the failed network, create a new post with only that account id; resending all three would trip duplicate_content on the ones that already published.

These are differences you don't see in the text itself but that change what readers get.

• X: every URL is wrapped by t.co and counts 23. Each link puts the post in X's $0.200 price tier instead of $0.015.
• Bluesky: links, @mentions and #hashtags become rich-text facets automatically; mentions are resolved to the account's DID. The URL text counts at full length.
• LinkedIn: the text is sent in LinkedIn's "little" text format. We escape the reserved characters ( ) [ ] { } < > @ | * _ ~ \ so they show as typed, and leave hashtags intact. An @name from X becomes plain text, not a LinkedIn mention.
• Images: X allows 4 (5 MB each), Bluesky 4 (2 MB each, per its lexicon), LinkedIn up to 20 (20 MB each). Sending 5 images to an X account fails preflight with too_many_media.

Each of these has an error code, so an agent can fix it without a human.

• One text for all networks: text_too_long on X. Add platform_options.x.text.
• Reposting to the same account: duplicate_content within 24 hours. Vary the wording per account or wait.
• Video in the media list: video_not_supported on every network for now. Use images.
• An account that needs reconnecting: account_needs_reauth on that target only. Send its owner a new connect link; the rest still publish.
• Too many accounts on the Free plan: plan_limit_active_accounts once a post would make more than 3 accounts active this month. See pricing.

If a person writes each post and wants to see it on a calendar, a dashboard scheduler is a better fit; we have no composer or calendar. We're built for crossposting from code: an app that posts on its users' behalf, a release pipeline, or an AI agent using our MCP server. X, Bluesky, LinkedIn, Mastodon and Telegram are live today. See the docs to start.