HappyHorse 1.1 API

Introduction

HappyHorse 1.1 Image to video animates an opening frame supplied in image_url. The prompt is required and describes the movement that follows; the clip runs 3 to 15 whole seconds at 720p or 1080p, with a generated soundtrack. There is no aspect-ratio field and no closing-frame field: the still sets the shape, and the ending is whatever the prompted movement resolves to.

Choose a HappyHorse 1.1 mode by starting material

Key features

The still sets subject and shape

In the tailgate-turn example the wardrobe, the truck and the backlight all come from the frame, and the prompt only asks her to lower the bottle, swing her boots once and turn her head into the low sun.

No closing frame to aim at

This endpoint takes image_url alone, so a shot cannot be pinned to a final composition. Movements that resolve on their own work best. The quiet-hold example is four seconds of near-stillness: a breath out, a dropped shoulder and a shift of weight against the window frame, with almost no camera movement.

Input and output limits

The opening frame needs at least 300 px on each side, an aspect ratio between 1:2.5 and 2.5:1 and a file size of up to 20 MB. Output runs 3 to 15 seconds with 5 as the default, at 720p (the default) or 1080p, and the soundtrack is always generated with the picture.

Request parameters

Pricing

Prices are in credits, the same credits you use on the website (1 credit = $0.01). The hold is taken when the task is accepted and settled to the actual charge when it finishes; failed tasks are refunded.

For an exact number before you run, send the same body to POST /jobs/quote.

Use cases

Environmental motion around a held pose

The wasteland-hood-two example keeps two figures on the hood of a stalled car and writes only what exists in motion: torn cloth lifted and dropped by the wind, a rippling heat haze, dust devils crossing the road and a slow push in. It ran at 1080p with the default duration.

Short inserts and cutaways

A clip of three or four seconds with minimal camera movement suits inserts between longer shots. Keep the action to one breath or one gesture, as quiet-hold does, so the movement completes inside the duration instead of being cut off mid-way.

Prompt guide & pro tips

Give the prompt only motion

The prompt is required, so use it for what changes: action, camera and pacing. The wasteland-hood-two prompt never describes the composition; it describes wind, haze and dust. Re-describing the frame spends the 2,500-character limit on what the image already fixes.

Size the movement to the duration

With no closing frame, a movement that cannot finish in the chosen time simply stops where the clip ends. Match the action to the length: one gesture for a short clip, or a short sequence such as lower, swing, turn for a longer one, as tailgate-turn does over six seconds.

Crop before you upload

The still decides the output shape, so crop it to the delivery aspect ratio first and check it against the size limits. Draft at 720p and re-run at 1080p for delivery. Each pass draws its own take, so keep the wording fixed while you compare.

API quick start

Call the HappyHorse 1.1 API in three steps

1. Create an API key. Sign in to PopNow and create a key in the API console. Keys start with sk-popnow- and use the same credits as the website.
2. Send the request. POST /jobs/createTask with model alibaba/happyhorse-1.1/image-to-video and an input object that follows the parameter table. The response returns a task ID straight away.
3. Get the result. Poll GET /jobs/recordInfo with the task ID, or pass a callBackUrl and we post the result to it. Download the output links when the task succeeds.

# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(uuidgen)"
curl -X POST https://api.popnow.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $IDEMPOTENCY_KEY" \
  -d '{
  "model": "alibaba/happyhorse-1.1/image-to-video",
  "input": {
    "prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
    "image_url": "https://media.popnow.ai/influencer/examples/marco.webp",
    "resolution": "720p",
    "duration_seconds": 5
  }
}'

# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $POPNOW_API_KEY"

Replace the prompt and any links with your own. The API tab has the response, polling and callback reference.

HappyHorse 1.1 API questions

Other video APIs

• MiniMax H3 APIExpressive clips with audio, up to 2KFrom 28 credits for a 5-second clip
• Wan 3.0 APIUp to 30-second clips with synced audioFrom 34 credits for a 5-second clip
• Wan 3.0 Prime APIQuicker Wan 3.0 renders, up to 30 seconds with audioFrom 46 credits for a 5-second clip
• Seedance 2.5 APIByteDance's newest: 30-second clips with native audioFrom 56 credits for a 5-second clip
• Kling 3.0 API4K clips, multi-shot cuts and motion controlFrom 51 credits for a 5-second clip
• Vidu Q4 Preview APIUp to 4K clips with sound and spoken dialogueFrom 34 credits for a 5-second clip

More about HappyHorse 1.1

Try it

HappyHorse 1.1 AI Video Generator onlineCreate videos with HappyHorse 1.1 in PopNow

Docs

HappyHorse 1.1 model ID and input schema in the API docsPopNow API quickstart: your first request in five minutesImage to video guide for the PopNow APIWebhooks: get HappyHorse 1.1 results without polling