Facebook API: Posting Reference
Facebook is supported via the Facebook Graph API. OmniSocials posts to Facebook Pages (not personal profiles). The Facebook Page must be administered by the user who connects the account.
Channel ID: facebook
Supported content types
| Type | Supported | Notes |
|---|---|---|
| Feed post | ✅ | Text, image, video, carousel, or link preview |
| Story | ✅ | Image or video. Up to 10 slides per post, each published as its own story in order |
| Reel | ✅ | Vertical video |
Minimal example
Code
Unlike Instagram, Facebook accepts text-only posts with no media.
Platform-specific options
Set these under the facebook key on the post body:
| Field | Type | Description |
|---|---|---|
facebook.first_comment | string | Text auto-posted as the first comment right after the post publishes (max 8000 characters). Page posts only; the API cannot comment on personal profiles. Not posted for stories. |
Facebook has no required option fields. Aside from the optional first comment, the default create-post body is sufficient for most use cases.
Media requirements
| Media | Requirement |
|---|---|
| Image | JPEG, PNG, GIF, or WebP (WebP is transcoded to JPEG at post time). Max 10 MB. |
| Video | MP4 or MOV, up to 240 minutes, max 1 GB |
| Story image | JPEG or PNG, 9:16 recommended |
| Story video | MP4, up to 60 seconds per slide |
| Reel video | MP4, vertical 9:16, 3 to 90 seconds |
| Carousel | 2 to 10 images |
Facebook 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. Per-media alt entries are accepted but not delivered; the platform's API does not support alt text on third-party posts. It is safe to send the same media objects you use for other platforms.
Character limit
63,206 characters per post. In practice you will never hit it; write for readers, not the cap.
Limitations
- Personal Facebook profiles (not Pages) are not supported
- Posts to Groups are not currently supported
- Link previews are generated automatically from the first URL in the post content when no media is attached
- Facebook's API does not guarantee delivery timing for scheduled posts. Expect publish times within a few minutes of the scheduled time.