---
title: Imagen 4 Fast | Runware Docs
url: https://runware.ai/docs/models/google-imagen-4-fast
description: High speed Imagen 4 Fast text to image generation
---
# Imagen 4 Fast

Imagen 4 Fast is a latency optimized text to image model in the Imagen 4 family. It targets interactive apps and high volume pipelines. It keeps strong Imagen 4 visual quality while cutting generation time, so teams can iterate faster and reduce serving costs in production.

- **ID**: `google:2@3`
- **Status**: live
- **Creator**: Google
- **Release Date**: June 6, 2025
- **Capabilities**: Text to Image

## Pricing

~$0.0185 per megapixel

- **1024x1024 (1:1)**: `$0.02`
- **1408x768 (16:9)**: `$0.02`
- **768x1408 (9:16)**: `$0.02`
- **1280x896 (4:3)**: `$0.02`
- **896x1280 (3:4)**: `$0.02`

## Compatibility & Validation

`width` and `height` must be used together.

---

The following dimension combinations are supported:

| Configuration | Dimensions |
| --- | --- |
| `1K (1:1)` | `1024x1024` |
| `1K (9:16)` | `768x1408` |
| `1K (16:9)` | `1408x768` |
| `1K (7:10)` | `896x1280` |
| `1K (10:7)` | `1280x896` |

## Request Parameters

**API Options**

Platform-level options for task execution and delivery.

### [taskType](https://runware.ai/docs/models/google-imagen-4-fast#request-tasktype)

- **Type**: `string`
- **Required**: true
- **Value**: `imageInference`

Identifier for the type of task being performed

### [taskUUID](https://runware.ai/docs/models/google-imagen-4-fast#request-taskuuid)

- **Type**: `string`
- **Required**: true
- **Format**: `UUID v4`

UUID v4 identifier for tracking tasks and matching async responses. Must be unique per task.

### [outputType](https://runware.ai/docs/models/google-imagen-4-fast#request-outputtype)

- **Type**: `string`
- **Default**: `URL`

Image output type.

**Allowed values**: `URL` `base64Data` `dataURI`

### [outputFormat](https://runware.ai/docs/models/google-imagen-4-fast#request-outputformat)

- **Type**: `string`
- **Default**: `JPG`

Specifies the file format of the generated output. The available values depend on the task type and the specific model's capabilities.

- \`JPG\`: Best for photorealistic images with smaller file sizes (no transparency).
- \`PNG\`: Lossless compression, supports high quality and transparency (alpha channel).
- \`WEBP\`: Modern format providing superior compression and transparency support.

> [!NOTE]
> \*\*Transparency\*\*: If you are using features like background removal or LayerDiffuse that require transparency, you must select a format that supports an alpha channel (e.g., \`PNG\`, \`WEBP\`, \`TIFF\`). \`JPG\` does not support transparency.

**Allowed values**: `JPG` `PNG` `WEBP`

### [outputQuality](https://runware.ai/docs/models/google-imagen-4-fast#request-outputquality)

- **Type**: `integer`
- **Min**: `20`
- **Max**: `99`
- **Default**: `95`

Compression quality of the output. Higher values preserve quality but increase file size.

### [webhookURL](https://runware.ai/docs/models/google-imagen-4-fast#request-webhookurl)

- **Type**: `string`
- **Format**: `URI`

Specifies a webhook URL where JSON responses will be sent via HTTP POST when generation tasks complete. For batch requests with multiple results, each completed item triggers a separate webhook call as it becomes available.

**Learn more** (1 resource):

- [Webhooks](https://runware.ai/docs/platform/webhooks) (platform)

### [deliveryMethod](https://runware.ai/docs/models/google-imagen-4-fast#request-deliverymethod)

- **Type**: `string`
- **Default**: `sync`

Determines how the API delivers task results.

**Allowed values**:

- `sync` Returns complete results directly in the API response.
- `async` Returns an immediate acknowledgment with the task UUID. Poll for results using getResponse.

**Learn more** (1 resource):

- [Task Polling](https://runware.ai/docs/platform/task-polling) (platform)

### [uploadEndpoint](https://runware.ai/docs/models/google-imagen-4-fast#request-uploadendpoint)

- **Type**: `string`
- **Format**: `URI`

Specifies a URL where the generated content will be automatically uploaded using the HTTP PUT method. The raw binary data of the media file is sent directly as the request body. For secure uploads to cloud storage, use presigned URLs that include temporary authentication credentials.

**Common use cases:**

- **Cloud storage**: Upload directly to S3 buckets, Google Cloud Storage, or Azure Blob Storage using presigned URLs.
- **CDN integration**: Upload to content delivery networks for immediate distribution.

```text
// S3 presigned URL for secure upload
https://your-bucket.s3.amazonaws.com/generated/content.mp4?X-Amz-Signature=abc123&X-Amz-Expires=3600

// Google Cloud Storage presigned URL
https://storage.googleapis.com/your-bucket/content.jpg?X-Goog-Signature=xyz789

// Custom storage endpoint
https://storage.example.com/uploads/generated-image.jpg
```

The content data will be sent as the request body to the specified URL when generation is complete.

### [safety](https://runware.ai/docs/models/google-imagen-4-fast#request-safety)

- **Path**: `safety.checkContent`
- **Type**: `object (2 properties)`

Content safety checking configuration for image generation.

#### [checkContent](https://runware.ai/docs/models/google-imagen-4-fast#request-safety-checkcontent)

- **Path**: `safety.checkContent`
- **Type**: `boolean`
- **Default**: `false`

Enable or disable content safety checking. When enabled, defaults to `fast` mode.

#### [mode](https://runware.ai/docs/models/google-imagen-4-fast#request-safety-mode)

- **Path**: `safety.mode`
- **Type**: `string`
- **Default**: `none`

Safety checking mode for image generation.

**Allowed values**:

- `none` Disables checking.
- `fast` Performs a single check.

### [ttl](https://runware.ai/docs/models/google-imagen-4-fast#request-ttl)

- **Type**: `integer`
- **Min**: `60`

Time-to-live (TTL) in seconds for generated content. Only applies when `outputType` is `URL`.

### [includeCost](https://runware.ai/docs/models/google-imagen-4-fast#request-includecost)

- **Type**: `boolean`
- **Default**: `false`

Include task cost in the response.

### [numberResults](https://runware.ai/docs/models/google-imagen-4-fast#request-numberresults)

- **Type**: `integer`
- **Min**: `1`
- **Max**: `20`
- **Default**: `1`

Number of results to generate. Each result uses a different seed, producing variations of the same parameters.

**Generation Parameters**

Core parameters for controlling the generated content.

### [model](https://runware.ai/docs/models/google-imagen-4-fast#request-model)

- **Type**: `string`
- **Required**: true
- **Value**: `google:2@3`

Identifier of the model to use for generation.

**Learn more** (3 resources):

- [Text To Image: Model Selection The Foundation Of Generation](https://runware.ai/docs/guides/text-to-image#model-selection-the-foundation-of-generation) (guide)
- [Image Inpainting: Model Specialized Inpainting Models](https://runware.ai/docs/guides/image-inpainting#model-specialized-inpainting-models) (guide)
- [Image Outpainting: Other Critical Parameters](https://runware.ai/docs/guides/image-outpainting#other-critical-parameters) (guide)

### [positivePrompt](https://runware.ai/docs/models/google-imagen-4-fast#request-positiveprompt)

- **Type**: `string`
- **Required**: true
- **Min**: `2`
- **Max**: `3000`

Text prompt describing elements to include in the generated output.

**Learn more** (2 resources):

- [Text To Image: Prompts Guiding The Generation](https://runware.ai/docs/guides/text-to-image#prompts-guiding-the-generation) (guide)
- [Image Outpainting: Other Critical Parameters](https://runware.ai/docs/guides/image-outpainting#other-critical-parameters) (guide)

### [width](https://runware.ai/docs/models/google-imagen-4-fast#request-width)

- **Type**: `integer`
- **Required**: true
- **Paired with**: height

Width of the generated media in pixels.

**Learn more** (2 resources):

- [Image To Image: Dimensions Changing Aspect Ratio](https://runware.ai/docs/guides/image-to-image#dimensions-changing-aspect-ratio) (guide)
- [Image Outpainting: Dimensions Critical For Outpainting](https://runware.ai/docs/guides/image-outpainting#dimensions-critical-for-outpainting) (guide)

### [height](https://runware.ai/docs/models/google-imagen-4-fast#request-height)

- **Type**: `integer`
- **Required**: true
- **Paired with**: width

Height of the generated media in pixels.

**Learn more** (2 resources):

- [Image To Image: Dimensions Changing Aspect Ratio](https://runware.ai/docs/guides/image-to-image#dimensions-changing-aspect-ratio) (guide)
- [Image Outpainting: Dimensions Critical For Outpainting](https://runware.ai/docs/guides/image-outpainting#dimensions-critical-for-outpainting) (guide)

## Response Parameters

### [taskType](https://runware.ai/docs/models/google-imagen-4-fast#response-tasktype)

- **Type**: `string`
- **Required**: true
- **Value**: `imageInference`

Type of the task.

### [taskUUID](https://runware.ai/docs/models/google-imagen-4-fast#response-taskuuid)

- **Type**: `string`
- **Required**: true
- **Format**: `UUID v4`

UUID of the task.

### [imageUUID](https://runware.ai/docs/models/google-imagen-4-fast#response-imageuuid)

- **Type**: `string`
- **Required**: true
- **Format**: `UUID v4`

UUID of the output image.

### [imageURL](https://runware.ai/docs/models/google-imagen-4-fast#response-imageurl)

- **Type**: `string`
- **Format**: `URI`

URL of the output image.

### [imageBase64Data](https://runware.ai/docs/models/google-imagen-4-fast#response-imagebase64data)

- **Type**: `string`

Base64-encoded image data.

### [imageDataURI](https://runware.ai/docs/models/google-imagen-4-fast#response-imagedatauri)

- **Type**: `string`
- **Format**: `URI`

Data URI of the output image.

### [seed](https://runware.ai/docs/models/google-imagen-4-fast#response-seed)

- **Type**: `integer`

The seed used for generation. If none was provided, shows the randomly generated seed.

### [NSFWContent](https://runware.ai/docs/models/google-imagen-4-fast#response-nsfwcontent)

- **Type**: `boolean`

Flag indicating if NSFW content was detected.

### [cost](https://runware.ai/docs/models/google-imagen-4-fast#response-cost)

- **Type**: `float`

Task cost in USD. Present when `includeCost` is set to `true` in the request.

## Examples

### Flooded Cathedral Transit Hall (Text to Image)

![Flooded Cathedral Transit Hall](https://assets.runware.ai/examples/google-imagen-4-fast/e0fe6024-e3bc-4128-9305-bcd2f82644be.jpg)

**Request**:

```json
{
  "taskType": "imageInference",
  "taskUUID": "7c28b0f9-2464-4e88-b21e-b29e455a5fe6",
  "model": "google:2@3",
  "positivePrompt": "A vast abandoned railway terminal redesigned inside a soaring gothic cathedral nave, ankle-deep clear floodwater across polished stone floors, commuters wading between brass luggage carts and floating paper lanterns, colossal ribbed vaults overhead, stained glass casting fractured amber, teal, and crimson reflections across the water, a suspended arrival board with partially missing letters, distant platform arches disappearing into mist, swallows circling near the ceiling, bundles of wild reeds growing through cracked tiles, one sleek silver train standing still like a relic, cinematic wide shot, intricate environmental storytelling, ultra-detailed textures, atmospheric depth, realistic lighting, sharp focus, majestic scale, vivid but natural color grading",
  "width": 1408,
  "height": 768
}
```

**Response**:

```json
{
  "taskType": "imageInference",
  "taskUUID": "7c28b0f9-2464-4e88-b21e-b29e455a5fe6",
  "imageUUID": "8978d335-5674-4a7d-b15a-e439d9265a2d",
  "imageURL": "https://im.runware.ai/image/os/a12d13/ws/2/ii/8978d335-5674-4a7d-b15a-e439d9265a2d.jpg",
  "seed": 1348345038,
  "cost": 0.02
}
```

---

### Wind-Carved Desert Caravanserai (Text to Image)

![Wind-Carved Desert Caravanserai](https://assets.runware.ai/examples/google-imagen-4-fast/4e2dc2cf-2655-419e-b533-42948fd077ab.jpg)

**Request**:

```json
{
  "taskType": "imageInference",
  "taskUUID": "9d983fa3-1624-4d66-9501-6a5a5b2c7cfb",
  "model": "google:2@3",
  "positivePrompt": "A vast desert caravanserai built inside the ribbed remains of an ancient fossilized sea creature, half-buried in sweeping amber dunes; weathered sandstone arches, woven shade canopies, suspended brass lanterns, tethered pack animals, traders in layered textiles, ceramic jars, rolled carpets, and carved wooden chests scattered through a bustling courtyard. In the distance, tall wind-shaped rock spires and a pale turquoise dry basin shimmer under a bright late-afternoon sky with streaky clouds. Fine airborne dust catches warm sunlight, creating soft volumetric haze and long elegant shadows. Ultra-detailed materials, intricate textures, believable human scale, dynamic composition, wide cinematic framing, realistic lighting, sharp focus, richly colored yet natural palette, immersive worldbuilding, premium travel photography aesthetic.",
  "width": 1408,
  "height": 768
}
```

**Response**:

```json
{
  "taskType": "imageInference",
  "taskUUID": "9d983fa3-1624-4d66-9501-6a5a5b2c7cfb",
  "imageUUID": "51c84c45-1760-42f8-a723-19ba3a00a9f9",
  "imageURL": "https://im.runware.ai/image/os/a07d11/ws/2/ii/51c84c45-1760-42f8-a723-19ba3a00a9f9.jpg",
  "seed": 1943620252,
  "cost": 0.02
}
```

---

### Subterranean Glass Orchard Concourse (Text to Image)

![Subterranean Glass Orchard Concourse](https://assets.runware.ai/examples/google-imagen-4-fast/d17ed4a7-a29b-46fa-be8c-8f62d0da09ec.jpg)

**Request**:

```json
{
  "taskType": "imageInference",
  "taskUUID": "29a8aa01-b80c-4643-abea-db27589c7c38",
  "model": "google:2@3",
  "positivePrompt": "A vast underground transit concourse transformed into a thriving glass-roofed orchard, terraced citrus trees and hanging vines growing between elegant stone platforms and sleek commuter walkways, travelers carrying lacquered suitcases and baskets of fruit, polished brass railings, patterned tile floors, shafts of warm daylight filtering through cracked crystal panels in the ceiling, drifting dust, distant arrival boards, shallow reflective water channels, subtle steam from vents, highly detailed environmental storytelling, cinematic wide shot, intricate textures, believable scale, crisp focus, natural color harmony, premium commercial photography look",
  "width": 1408,
  "height": 768
}
```

**Response**:

```json
{
  "taskType": "imageInference",
  "taskUUID": "29a8aa01-b80c-4643-abea-db27589c7c38",
  "imageUUID": "2df0ca74-e3eb-444f-aafa-44b01fd6f433",
  "imageURL": "https://im.runware.ai/image/os/a20d05/ws/2/ii/2df0ca74-e3eb-444f-aafa-44b01fd6f433.jpg",
  "seed": 1855629850,
  "cost": 0.02
}
```

---

### Rainy Tram Depot Reverie (Text to Image)

![Rainy Tram Depot Reverie](https://assets.runware.ai/examples/google-imagen-4-fast/e7052e4e-390b-42d4-93e1-ded986e4f867.jpg)

**Request**:

```json
{
  "taskType": "imageInference",
  "taskUUID": "b20a1b78-235b-40f7-aa12-29fadd35d91c",
  "model": "google:2@3",
  "positivePrompt": "A vast early-morning tram depot inside a century-old iron-and-glass transit hall during a spring downpour, polished rails and puddled stone flooring reflecting warm amber station lamps, several vintage trams in faded saffron, moss green, and oxblood red lined up beneath hanging route placards, mechanics in waterproof coats checking cables and wheels, a florist's abandoned handcart spilling peonies and ferns near a bench, flocks of swallows circling under the arched roof, steam rising from vents, distant city towers softened by rain through towering windows, cinematic depth, intricate architectural detail, realistic materials, expressive weather, balanced composition, crisp focus, natural color harmony, premium photography look",
  "width": 1408,
  "height": 768
}
```

**Response**:

```json
{
  "taskType": "imageInference",
  "taskUUID": "b20a1b78-235b-40f7-aa12-29fadd35d91c",
  "imageUUID": "4172489a-291d-410b-8754-1a3aea5ff60e",
  "imageURL": "https://im.runware.ai/image/os/a11d13/ws/2/ii/4172489a-291d-410b-8754-1a3aea5ff60e.jpg",
  "seed": 1320781308,
  "cost": 0.02
}
```