# Seedream v5.5 Text-to-Image — Atlas Cloud API

> ByteDance Seedream 5.5 text-to-image model that generates one photorealistic image from a prompt, with accurate small and multilingual text and native transparent (RGBA) PNG output.

This is the machine-readable API reference for **Seedream v5.5 Text-to-Image** on Atlas Cloud,
a unified API platform for 400+ AI models across text, image, video, audio and 3D.

- **Model ID**: `bytedance/seedream-v5.5/text-to-image`
- **Built by**: ByteDance
- **Modality**: Image
- **Model page**: https://www.atlascloud.ai/models/bytedance/seedream-v5.5/text-to-image
- **API key**: https://www.atlascloud.ai/console/api-keys
- **Docs**: https://www.atlascloud.ai/docs

## Pricing on Atlas Cloud

- $0.016 per image
- Pay-as-you-go. No minimum spend, no subscription required.

> **These are the authoritative Atlas Cloud rates for this model.** Any price that
> appears in the vendor description further down refers to a different platform or
> a different model variant and does not apply here.

## Use this model from an AI agent

Atlas Cloud ships three first-party integration surfaces. All three authenticate
with the same API key via the `ATLASCLOUD_API_KEY` environment variable.

### MCP server

The official MCP server (`atlascloud-mcp`) exposes this model to any
MCP-compatible host — Claude Code, OpenAI Codex, Cursor, Gemini CLI, Goose,
Claude Desktop. One-line install:

```bash
# Claude Code
claude mcp add atlascloud -- npx -y atlascloud-mcp

# OpenAI Codex CLI
codex mcp add atlascloud -- npx -y atlascloud-mcp

# Gemini CLI
gemini mcp add atlascloud -- npx -y atlascloud-mcp

export ATLASCLOUD_API_KEY="your-api-key"
```

Then ask in plain English; the agent calls `atlas_generate_image` with `model: "bytedance/seedream-v5.5/text-to-image"`.
The server fetches each model's schema and validates parameters before submitting,
so invalid requests fail fast without spending credits.

MCP docs: https://www.atlascloud.ai/docs/mcp-server

### Agent Skills

`atlas-cloud-skills` is a portable skill package (API reference, code templates in
Python / Node.js / cURL, model IDs with pricing) for Claude Code, Cursor, Codex and
12+ other agents:

```bash
npx skills add AtlasCloudAI/atlas-cloud-skills
export ATLASCLOUD_API_KEY="your-api-key"
```

Skills docs: https://www.atlascloud.ai/docs/skills

### CLI

The `atlas` binary runs Atlas Cloud from a terminal or CI script. Async media jobs
are polled and downloaded automatically (use `--no-download` when a script only
needs the output URLs):

```bash
# Install (Homebrew, npm, or shell installer)
brew install AtlasCloudAI/tap/atlascloud
# npm install -g atlascloud-cli
# curl -fsSL https://raw.githubusercontent.com/AtlasCloudAI/cli/main/install.sh | sh

atlas auth login
atlas generate image bytedance/seedream-v5.5/text-to-image -p "Your prompt here"
```

CLI docs: https://www.atlascloud.ai/docs/cli

## HTTP API reference

- **Submit endpoint (POST)**: `https://api.atlascloud.ai/api/v1/model/generateImage` — start an async generation; returns a `prediction_id`
- **Poll endpoint (GET)**: `https://api.atlascloud.ai/api/v1/model/prediction/{prediction_id}` — poll this until the prediction finishes
- **Model ID**: `bytedance/seedream-v5.5/text-to-image`


## API Information

This model can be used via our HTTP API or more conveniently via our client libraries.
See the input and output schema below, as well as the usage examples.


### Input Schema

The API accepts the following input parameters:

- **`model`** (`string`, _required_):
  model name
  - Default: `"bytedance/seedream-v5.5/text-to-image"`

- **`prompt`** (`string`, _required_):
  The text prompt describing the image to generate. Recommended length: within 300 Chinese characters or 600 English words.

- **`size`** (`string`, _optional_):
  Output image size in width*height pixels, in aspect ratios 1:1, 4:3, 3:4, 16:9, 9:16, 3:2, 2:3 and 21:9. Offers the largest size of each aspect ratio within the pixel limit (e.g., 2880*2880, 3840*2160) plus the official presets of the 2k, 1.5k and 1k tiers. The product of width × height is within [921,600 (1280*720), 8,294,400 (2880*2880)].
  - Default: `"2048*2048"`
  - Options: "2880*2880", "3264*2448", "2448*3264", "3840*2160", "2160*3840", "3504*2336", "2336*3504", "4368*1872", "2048*2048", "2368*1776", "1776*2368", "2816*1584", "1584*2816", "2496*1664", "1664*2496", "3136*1344", "1536*1536", "1792*1344", "1344*1792", "2048*1152", "1152*2048", "1872*1248", "1248*1872", "2352*1008", "1024*1024", "1152*864", "864*1152", "1424*800", "800*1424", "1248*832", "832*1248", "1568*672"

- **`output_format`** (`string`, _optional_):
  Output image file format. A jpeg output is always opaque: with background set to auto the result is opaque, and background set to transparent is rejected.
  - Default: `"png"`
  - Options: "png", "jpeg"

- **`background`** (`string`, _optional_):
  Controls whether the generated image has a transparent background (alpha channel). 'auto' (default) lets the model decide from the prompt and output_format; a jpeg output is always opaque. 'transparent' outputs an RGBA image with a transparent background and requires output_format png. 'opaque' outputs an RGB image with an opaque background. The background type actually used is returned in image_results[].background.
  - Default: `"auto"`
  - Options: "auto", "transparent", "opaque"

- **`enable_sync_mode`** (`boolean`, _optional_):
  If set to true, the function will wait for the result to be generated and uploaded before returning the response. It allows you to get the result directly in the response. This property is only available through the API.
  - Default: `false`

- **`enable_base64_output`** (`boolean`, _optional_):
  If enabled, the output will be encoded into a BASE64 string instead of a URL. This property is only available through the API.
  - Default: `false`



**Required Parameters Example**:

```json
{
  "model": "bytedance/seedream-v5.5/text-to-image",
  "prompt": ""
}
```


**Full Example**:

```json
{
  "model": "bytedance/seedream-v5.5/text-to-image",
  "prompt": "",
  "size": "2048*2048",
  "output_format": "png",
  "background": "auto",
  "enable_sync_mode": false,
  "enable_base64_output": false
}
```


### Output Schema

The API returns the following output format:


- **`code`** (`integer`, _optional_):
  Status code of the call; 200 on success.

- **`message`** (`string`, _optional_):
  Status message of the call.

- **`data`** (`object`, _optional_):
  The prediction: id, model, status, outputs, image_results, urls and created_at. Poll GET /api/v1/model/prediction/{request_id} with data.id until status is completed or failed.



**Example Response**:

```json
{
  "code": 0,
  "message": "",
  "data": {}
}
```


## Usage Examples

### cURL

```bash
# Step 1: Start generation (async)
curl -X POST "https://api.atlascloud.ai/api/v1/model/generateImage" \
  -H "Authorization: Bearer $ATLASCLOUD_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "bytedance/seedream-v5.5/text-to-image",
  "prompt": "",
  "size": "2048*2048",
  "output_format": "png",
  "background": "auto",
  "enable_sync_mode": false,
  "enable_base64_output": false
}'

# Response will contain: {"code": 200, "data": {"id": "prediction_id", "status": "processing"}}

# Step 2: Poll for result (replace {prediction_id} with the id returned above)
curl -X GET "https://api.atlascloud.ai/api/v1/model/prediction/{prediction_id}" \
  -H "Authorization: Bearer $ATLASCLOUD_API_KEY"

# Keep polling until status is "completed", "succeeded" or "failed"
# When completed, outputs will contain the generated content URL(s)
```

## Additional Resources

### Documentation

- [Model Playground](https://www.atlascloud.ai/models/bytedance/seedream-v5.5/text-to-image)

## About this model

_Vendor-supplied description. Any pricing or endpoint mentioned below refers to_
_other platforms — use the Atlas Cloud values above._

#### ByteDance Seedream 5.5 — Text-to-Image

**Seedream 5.5** (version 261028, October 2026) is the latest image generation and editing model from ByteDance's Seed team and the successor to Seedream 5.0 Pro. ByteDance positions it as a **production-grade "AI Photoshop"** and alongside the world's leading image models. A single model generates images, keeps them consistent through many rounds of editing, outputs native transparent (RGBA) images, and splits a finished image back into editable layers. Compared with Seedream 5.0 Pro, it improves photorealism, aesthetics and editing consistency. It supports continuous multi-round editing while keeping non-edited areas stable, and it adds three new capabilities: **native RGBA output**, **layer decomposition into up to 100 images**, and **rich-text OCR** of regular text.

This **Text-to-Image** endpoint generates **one image from a text prompt**. It runs the same Seedream 5.5 model as the Edit and Layer Decomposition endpoints; only the inputs differ. New in 5.5, you can set `background` to `transparent` and get a native RGBA image straight from a prompt. Seedream 5.0 Pro only supported transparency when editing an input PNG that already had an alpha channel.

#### 🌟 What's New in Seedream 5.5

_(Description truncated. Full text on the model page.)_

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Atlas Cloud — one API for 400+ AI models. Model page: https://www.atlascloud.ai/models/bytedance/seedream-v5.5/text-to-image · Docs: https://www.atlascloud.ai/docs