All 9 platforms at a glance
Compare all nine live platforms before committing to a workflow. Jump to a platform guide for the full detail.
Supported content types
| Platform | IMAGE | VIDEO | CAROUSEL | REEL | TEXT | THREAD | DOCUMENT |
|---|---|---|---|---|---|---|---|
| ✅ | ✅ | ✅ | ✅ | ✗ | ✗ | ✗ | |
| Twitter / X | ✅ | ✅ | ✗ | ✗ | ✅ | ✅ | ✗ |
| ✅ | ✅ | ✗ | ✗ | ✅ | ✗ | ✅ | |
| ✅ | ✅ | ✗ | ✗ | ✅ | ✗ | ✗ | |
| Threads | ✅ | ✅ | ✗ | ✗ | ✅ | ✗ | ✗ |
| YouTube | ✗ | ✅ | ✗ | ✗ | ✗ | ✗ | ✗ |
| Bluesky | ✅ | ✗ | ✗ | ✗ | ✅ | ✗ | ✗ |
| Mastodon | ✅ | ✅ | ✗ | ✗ | ✅ | ✗ | ✗ |
| WhatsApp Business | ✅ | ✅ | ✗ | ✗ | ✅ | ✗ | ✗ |
Text / caption limits
| Platform | Limit | Notes |
|---|---|---|
| 2,200 chars | Caption only — text-only posts are not supported | |
| Twitter / X | 280 chars | Links always count as 23 chars regardless of length |
| 3,000 chars | ||
| 63,206 chars | Effectively unlimited | |
| Threads | 500 chars | |
| YouTube | 5,000 chars | Video description, not a caption |
| Bluesky | 300 graphemes | Emoji = 1 grapheme each; different from characters |
| Mastodon | 500 chars* | *Default — varies by instance; some allow up to 5,000 |
| WhatsApp Business | 4,096 chars |
Media count limits
| Platform | Max images | Max videos | Can mix image + video? | Notes |
|---|---|---|---|---|
| 10 (carousel) | 10 (carousel) | ✅ | At least 1 image or video required on every post | |
| Twitter / X | 4 | 1 | ✗ | Cannot mix images and video in the same post |
| 9 | 1 | ✗ | PDF documents up to 100 MB supported | |
| 10 | 1 | ✗ | ||
| Threads | 10 | 1 | ✅ | |
| YouTube | — | 1 | — | Video-only; thumbnail is a companion image only |
| Bluesky | 4 | 0 | ✗ | No video support |
| Mastodon | 4 | 1 | ✗ | Default limits; may vary by instance |
| WhatsApp Business | 30 | 1 | ✗ |
Image limits
| Platform | Max image size | Max images | Aspect ratio | Notes |
|---|---|---|---|---|
| 8 MB | 10 | 4:5 – 1.91:1 | Min width 320px; out-of-range ratios rejected | |
| Twitter / X | 5 MB | 4 | Any | JPEG, PNG, GIF, WEBP |
| 8 MB | 9 | Any | ||
| 30 MB | 10 | Any | ||
| Threads | 8 MB | 10 | Any | |
| Bluesky | 1 MB | 4 | Any | Tight limit — compress images before uploading |
| Mastodon | 16 MB* | 4 | Any | *Default; varies by instance |
| WhatsApp Business | 5 MB | 30 | Any | JPEG or PNG |
YouTube and TikTok are video-only platforms for standard posts. YouTube thumbnails are uploaded separately.
Video limits
| Platform | Max video size | Max duration | Notes |
|---|---|---|---|
| 100 MB | 60 seconds (feed) | Use contentType: "REEL" for longer clips | |
| Twitter / X | 512 MB | 2:20 (140 sec) | |
| 5 GB | 10 minutes | ||
| 4 GB | 4 hours | ||
| Threads | 100 MB | 5 minutes | |
| YouTube | 256 GB | 12 hours | Upload directly to VoxBurst first; no raw mediaUrls |
| TikTok | 287 MB | 10 minutes | |
| Mastodon | 100 MB* | 5 minutes* | *Default; varies by instance |
| WhatsApp Business | 16 MB | 3 minutes | MP4 recommended |
Features and capabilities
| Platform | First comment | Scheduling | contentType required | Edit after publish |
|---|---|---|---|---|
| ✅ | ✅ | Yes | ✗ | |
| Twitter / X | ✅ | ✅ | No | ✗ |
| ✅ | ✅ | No | ✗ | |
| ✗ † | ✅ | No | ✗ | |
| Threads | ✅ | ✅ | No | ✗ |
| YouTube | ✅ | ✅ | No | ✗ |
| Bluesky | ✗ | ✅ | No | ✗ |
| Mastodon | ✗ | ✅ | No | ✗ |
| WhatsApp Business | ✗ | ✅ | No | ✗ |
Instagram Stories are not supported through the Graph API for third-party publishing. No platform in VoxBurst currently supports Stories.
† Facebook first comment — pending Meta API approval. The pages_manage_engagement permission required for Facebook first comments is under review by Meta. Posts with firstComment set will publish normally — the comment is silently skipped on Facebook until approval is granted.
“Edit after publish” refers to editing published content on the social platform itself via the API. None of the nine live platforms expose an edit endpoint through their third-party APIs. You can always edit a VoxBurst post in draft, scheduled, failed, or partial status via PATCH /v1/posts/:id — but once published the original cannot be updated programmatically.
Account requirements
| Platform | Account type required | Auth method | Key precondition |
|---|---|---|---|
| Business or Creator | OAuth via Facebook Graph API | Personal accounts not supported | |
| Twitter / X | Any account | OAuth 2.0 with PKCE | Token expires; re-connect if rejected |
| Personal or Company Page | OAuth 2.0 | Company page requires Admin or Content Admin role | |
| Page (not personal profile) | OAuth via Facebook Graph API | Page must be selected after connecting | |
| Threads | Instagram Business/Creator | OAuth (Meta) | Threads auth flows through Instagram — connect Instagram first |
| YouTube | YouTube channel | OAuth via Google | 6 upload/day quota; channel must have upload permissions |
| Bluesky | Any Bluesky account | App password | Re-generate app password at bsky.app if expired |
| Mastodon | Any Mastodon account | OAuth (per-instance) | Instance URL required at connection time |
| WhatsApp Business | WhatsApp Business Account (WABA) | OAuth via Meta Graph API | Requires Meta Business verification and a registered phone number ID |
Biggest gotchas
| Platform | #1 gotcha | #2 gotcha |
|---|---|---|
contentType required on every post | Aspect ratio must be 4:5–1.91:1 or image is rejected | |
| Twitter / X | Links count as 23 chars (280-char total) | Cannot mix image and video |
| Company page requires Admin role | PDF max 100 MB | |
| Must select a Page — personal profiles won’t publish | Re-connect if token expires (60–90 days) | |
| Threads | Instagram Business/Creator account must be connected first | First comment supported but Threads has limited thread depth |
| YouTube | 6 uploads/day quota — plan your schedule | Video must be uploaded to VoxBurst first; no raw mediaUrls |
| Bluesky | 300 graphemes, not 300 characters — emoji counts as 1 | 1 MB image limit is very tight — compress before uploading |
| Mastodon | Character limit varies by instance | Credentials are per-instance, not global |
| WhatsApp Business | Requires Meta Business verification and a WABA — cannot post from personal WhatsApp | No platformPostUrl returned — the Business API does not expose public post URLs |
Jump to a guide
- Post to Instagram via MCP
- Post to Twitter / X via MCP
- Post to LinkedIn via MCP
- Post to Facebook via MCP
- Post to Threads via MCP
- Post to YouTube via MCP
- Post to Bluesky via MCP
- Post to Mastodon via MCP
- Post to WhatsApp Business via MCP
Or see the same content posted across all 9 platforms for a direct comparison.
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