Seedance 2.5 Text to Video API

POST Base URL: https://api.hiapi.ai /v1/tasks

Image, video, and audio models are called through the Unified Async API POST /v1/tasks endpoint; only the input fields differ (see input parameters below).

Model summary

Model	seedance-2.5/text-to-video
Capability	Text-to-video
Resolution	480p / 720p
Duration	4-30 seconds

Generate a continuous clip of up to 30 seconds from text, with 480p or 720p output, seven aspect ratios, and synchronized audio.

Production guidance

Calling the API

Use callback.url for terminal notifications and GET /v1/tasks/:id as a fallback query.
Read the video artifact from the output item whose type is video.
Artifact URLs expire; copy files you need to keep into persistent storage.

Best suited for

Long-take storytelling

Generate 4-30 seconds in one task.

duration

Synchronized sound

Generate dialogue, ambience, effects, and background music with the picture.

generate_audio

Multiple formats

Create landscape, portrait, square, or 21:9 widescreen output.

aspect_ratio

Request parameters

POST https://api.hiapi.ai/v1/tasks

# Create an async task — returns taskId immediately (generation runs async)
# Replace YOUR_API_KEY with your account API key
curl -X POST "https://api.hiapi.ai/v1/tasks" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "seedance-2.5/text-to-video",
  "input": {
    "prompt": "A night train crossing a neon city in one continuous tracking shot, synchronized ambience and rail sounds",
    "resolution": "720p",
    "duration": 8,
    "aspect_ratio": "16:9",
    "generate_audio": true
  }
}'

import requests, json

# Business params — fields vary by model (see the model page)
payload = json.loads(r'''
{
  "model": "seedance-2.5/text-to-video",
  "input": {
    "prompt": "A night train crossing a neon city in one continuous tracking shot, synchronized ambience and rail sounds",
    "resolution": "720p",
    "duration": 8,
    "aspect_ratio": "16:9",
    "generate_audio": true
  }
}
''')

# Create an async task — returns taskId immediately (generation runs async)
resp = requests.post(
    "https://api.hiapi.ai/v1/tasks",
    headers={"Authorization": "Bearer YOUR_API_KEY", "Content-Type": "application/json"},
    json=payload,
)
print(resp.json())  # Returns { code, message, data: { taskId } }

// Create an async task — returns taskId immediately (generation runs async)
// Replace YOUR_API_KEY with your account API key
const resp = await fetch("https://api.hiapi.ai/v1/tasks", {
  method: "POST",
  headers: {
    "Authorization": "Bearer YOUR_API_KEY",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
  "model": "seedance-2.5/text-to-video",
  "input": {
    "prompt": "A night train crossing a neon city in one continuous tracking shot, synchronized ambience and rail sounds",
    "resolution": "720p",
    "duration": 8,
    "aspect_ratio": "16:9",
    "generate_audio": true
  }
}),
});
console.log(await resp.json()); // Returns { code, message, data: { taskId } }

model string required

Model ID.

example seedance-2.5/text-to-video

input object required

Text-to-video parameters.

prompt string required

Describe the video. Supported languages are Chinese, English, Spanish, Indonesian, Portuguese, Japanese, Malay, Thai, Arabic, Vietnamese, and Korean. Keep Chinese prompts within 500 characters or English prompts within 1,000 words for best results.

resolution enum optional

Output video resolution. Defaults to 480p.

default 480p enum: 480p720p

duration integer optional

Output duration in seconds. Accepts integers from 4 to 30 and defaults to 5 seconds.

default 5

aspect_ratio enum optional

Output aspect ratio. adaptive lets the model select a ratio from the prompt.

default adaptive enum: 16:94:31:13:49:1621:9adaptive

generate_audio boolean optional

Generate synchronized dialogue, effects, and background audio. Generated audio is mono.

default true

output_format enum optional

Output format. mp4 has broad compatibility; mov is intended for grading, keying, and compositing workflows.

default mp4 enum: mp4mov

watermark boolean optional

Add an AI-generated watermark to the bottom-right corner.

default false

web_search boolean optional

Allow the model to search for current information mentioned in the prompt. This may increase processing time.

default false

callback object optional

Sends the task object when the task reaches a terminal state; the polling endpoint wraps the same object in data.

url string required

HTTPS URL that receives terminal notifications.

example https://your-domain.com/hiapi/callback

when enum optional

Triggers when the task reaches a terminal state.

default final enum: final

Example requests

Basic text-to-video

Generate an 8-second 720p landscape clip.

Request body

{
  "model": "seedance-2.5/text-to-video",
  "input": {
    "prompt": "A misty valley at sunrise, slow push-in, distant birdsong",
    "resolution": "720p",
    "duration": 8,
    "aspect_ratio": "16:9"
  }
}

Silent vertical video

Disable generated audio for a later voice-over.