Imagen 4 API

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

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

Model summary

Model name	Google-Imagen4
Type	Image generation (text-to-image)
Endpoint	POST /v1/tasks
Pricing	See HiAPI Pricing

Imagen 4 text-to-image API for high-quality images from detailed prompts.

Production guidance

Pass callback.url at the top level in production to reduce polling.
Poll GET /v1/tasks/:id for local debugging.

Best suited for

Generate everyday product and content images

Product heroes, lifestyle visuals and campaign drafts in 6 aspect ratios; 16:9 by default.

promptaspect_ratio

Fix the seed to compare prompt changes

seed is a string of up to 500 characters; fix it to see only the prompt change.

seednegative_prompt

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": "Google-Imagen4",
  "input": {
    "prompt": "Create a premium skincare product photo for a landing-page hero. Show one frosted glass bottle on natural stone beside still water and green botanicals. Keep the bottle centered with empty space on the left for a headline. Warm daylight and soft shadows; the result should look like calm studio photography. Do not add logos or text.",
    "aspect_ratio": "16:9"
  }
}'

import requests, json

# Business params — fields vary by model (see the model page)
payload = json.loads(r'''
{
  "model": "Google-Imagen4",
  "input": {
    "prompt": "Create a premium skincare product photo for a landing-page hero. Show one frosted glass bottle on natural stone beside still water and green botanicals. Keep the bottle centered with empty space on the left for a headline. Warm daylight and soft shadows; the result should look like calm studio photography. Do not add logos or text.",
    "aspect_ratio": "16:9"
  }
}
''')

# 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": "Google-Imagen4",
  "input": {
    "prompt": "Create a premium skincare product photo for a landing-page hero. Show one frosted glass bottle on natural stone beside still water and green botanicals. Keep the bottle centered with empty space on the left for a headline. Warm daylight and soft shadows; the result should look like calm studio photography. Do not add logos or text.",
    "aspect_ratio": "16:9"
  }
}),
});
console.log(await resp.json()); // Returns { code, message, data: { taskId } }

model string required

Fixed value Google-Imagen4.

example Google-Imagen4

input object required

Put model parameters inside input.

prompt string required

Required image description, up to 5,000 characters.

aspect_ratio enum required

Output aspect ratio.

default 16:9 enum: 1:116:99:163:44:3auto

negative_prompt string optional

Optional negative prompt, up to 5,000 characters.

seed string optional

Optional string, up to 500 characters.

callback object optional

Optional terminal task callback.

url string required

HTTPS endpoint that receives terminal task notifications.

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

when enum optional

Callback timing; keep final.

default final enum: final

Example requests

Create a product hero with headline space

A four-part prompt: the task, what to show, what to keep, and texture and limits.

Request body

{
  "model": "Google-Imagen4",
  "input": {
    "prompt": "Create a premium skincare product photo for a landing-page hero. Show one frosted glass bottle on natural stone beside still water and green botanicals. Keep the bottle centered with empty space on the left for a headline. Warm daylight and soft shadows; the result should look like calm studio photography. Do not add logos or text.",
    "aspect_ratio": "16:9"
  }
}

Create a 3:4 documentary portrait

The prompt as submitted for an example on the model page.

Request body

{
  "model": "Google-Imagen4",
  "input": {
    "prompt": "Elderly fisherman mending nets on a harbor pier; golden hour; documentary portrait",
    "aspect_ratio": "3:4"
  }
}

Getting the result

The response returns a taskId immediately.
Wait for callback.url or poll GET /v1/tasks/:id.
When status=success, download output[].url.

FAQ

Does it accept reference images?

No. Imagen 4 generates from text only.

What type is seed?

An optional string of up to 500 characters.

Imagen 4, Fast or Ultra?

Use Imagen 4 for everyday production, imagen4-fast for many drafts, and imagen4-ultra when the final needs more detail.

How do I retrieve the result?

Use the taskId. The response returns it right away; download output[].url after the task succeeds.

How can I confirm the cost?

The task record is final. Check the pricing page and Playground estimate before submitting. View pricing