Grok Imagine Video Extend

What is Grok Imagine Video Extend?#

Grok Imagine Video Extend continues a video Grok Imagine already generated. You pass the task_id of the finished generation and choose how the continuation is driven: a preset, or your own prompt and timing.

It is the companion to the speed-optimized Grok Imagine Video route — the way to get past that model's 10-second ceiling by chaining continuations onto a video you like.

Key features of Grok Imagine Video Extend#

Best for#

Limitations#

Extend only accepts task IDs from Grok Imagine Video (xai/grok-imagine-video, the speed-optimized 1.5 build). Task IDs from Grok Imagine 1.5 Video are not supported — that route is the separate API build. Extensions are fixed at 6 or 10 seconds, and preset mode offers only spicy or normal. In custom mode all three of prompt, extend_at, and extend_duration are required; in preset mode they are ignored entirely.

API examples#

Call Grok Imagine Video Extend from any language by POSTing to /v1/tasks. Full parameter docs live at docs.unifically.com/models/video/xai/grok-imagine-video-extend.

Custom mode — you control the prompt and the timing:

curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "xai/grok-imagine-video-extend",
    "input": {
      "task_id": "abc123def456",
      "prompt": "The camera pulls back to reveal the whole street as the rain stops.",
      "extend_at": 4.5,
      "extend_duration": 6
    }
  }'

Preset mode — the preset drives the style, and prompt, extend_at, and extend_duration are ignored:

curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "xai/grok-imagine-video-extend",
    "input": {
      "task_id": "abc123def456",
      "video_preset": "normal"
    }
  }'

Successful submission returns a task_id of its own. Poll GET /v1/tasks/<task_id> or set a callback_url on the request to receive the finished video URL.