Schedule a post

curl -s \
  -H "Authorization: Bearer po_live_xxxxx_xxxxx" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: scheduled-launch-001" \
  -X POST https://postonce.to/api/public/v1/posts \
  -d '{
    "content": "Scheduled launch note",
    "publish_at": "2026-04-01T14:00:00.000Z",
    "targets": [
      { "account_id": "account-1" }
    ]
  }'

​

Supported follow-up actions

• GET /v1/posts/{id} to inspect the aggregate scheduled post
• PATCH /v1/posts/{id} to update it before it runs
• POST /v1/posts/{id}/publish to run it now
• POST /v1/posts/{id}/cancel or DELETE /v1/posts/{id} to cancel it

​

Custom video covers

{
  "content": "New episode is live",
  "publish_at": "2026-04-01T14:00:00.000Z",
  "media": [
    {
      "url": "https://cdn.example.com/episode.mp4",
      "type": "video",
      "thumbnail_url": "https://cdn.example.com/episode-cover.jpg"
    }
  ],
  "targets": [
    { "account_id": "instagram-account-id" },
    { "account_id": "facebook-account-id" },
    { "account_id": "tiktok-account-id" }
  ]
}

• Use a JPEG or PNG of 8 MB or less, at the same aspect ratio as the video.
• TikTok’s API has no field for a cover image, so PostOnce inserts the image as the first frame of the video, which TikTok then uses as the cover.
• To use a frame of the video as the TikTok cover instead, set platform_options.video_cover_timestamp_ms on the TikTok target. This works for direct video posts only, not photo posts or draft uploads, and it takes precedence over thumbnail_url for that target.
• Covers aren’t applied to video items inside Instagram carousels.