Seedream 5.5 Pro

Use Seedream 5.5 Pro through AnyFast for text-to-image generation, reference-image editing, and transparent image output. The request model ID is seedream-5-5-pro. ByteDance’s Seedream 5.5 announcement describes the series’ multi-turn editing, native RGBA, realism, and text-rendering capabilities.

To request transparent output, set background to transparent and output_format to png. A request without background: "transparent" returns an opaque image.

Key capabilities

Text to image — Create images from natural-language prompts with realistic textures and clear rendered text
Image editing — Refine a reference image over multiple turns while preserving regions outside the requested edit
Transparent background — Generate images with full or partial transparency in native RGBA output

Text to image
Image editing
Transparent background

Generate from text

curl https://www.anyfast.ai/v1/images/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedream-5-5-pro",
    "prompt": "A lifelike editorial photograph of a ceramic teapot on a wooden table, soft morning window light, fine glaze and wood textures",
    "size": "1K",
    "response_format": "url",
    "output_format": "png",
    "watermark": false
  }'

import requests

response = requests.post(
    "https://www.anyfast.ai/v1/images/generations",
    headers={
        "Authorization": "Bearer YOUR_API_KEY",
        "Content-Type": "application/json",
    },
    json={
        "model": "seedream-5-5-pro",
        "prompt": "A lifelike editorial photograph of a ceramic teapot on a wooden table, soft morning window light, fine glaze and wood textures",
        "size": "1K",
        "response_format": "url",
        "output_format": "png",
        "watermark": False,
    },
)

print(response.json())

The Seedream 5.5 series is designed to render lighting, materials, and skin textures naturally and to improve text rendering. Describe the intended composition, materials, lighting, and any exact text in the prompt.

Edit or refine a reference image

cURL

curl https://www.anyfast.ai/v1/images/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedream-5-5-pro",
    "prompt": "Change the blue scarf to forest green. Preserve the subject, pose, background, lighting, and all other details.",
    "image": "https://example.com/source-image.png",
    "size": "1K",
    "response_format": "url",
    "output_format": "png",
    "watermark": false
  }'

For multi-turn editing, pass the latest generated image as image in the next request. State which region or element to change and which details to preserve. ByteDance describes pixel-level preservation of unchanged regions across successive Seedream 5.5 edits.

ByteDance demonstration of successive Seedream 5.5 edits while preserving the rest of an image — Official Seedream 5.5 multi-turn editing example (announcement model). Source: ByteDance Seed.

Generate a transparent image

cURL

curl https://www.anyfast.ai/v1/images/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedream-5-5-pro",
    "prompt": "A detailed snowy owl in flight, isolated asset, transparent background outside the owl, preserve fine feather edges",
    "size": "1K",
    "response_format": "url",
    "output_format": "png",
    "background": "transparent",
    "watermark": false
  }'

Seedream 5.5 supports full and partial transparency. Use PNG output to retain the alpha channel.

ByteDance demonstration of image assets generated with transparent backgrounds — Official Seedream 5.5 transparent-asset example (announcement model). Source: ByteDance Seed.

Output controls

Parameter	Values	Notes
`size`	`1K`, `1.5K`, `2K`	The response reports actual image dimensions in `data[].size`: `1K` returned `1248x832`, `1.5K` returned `1888x1248`, and `2K` returned `2512x1680`.
`response_format`	`url`, `b64_json`	Returns a temporary URL or Base64 image data.
`output_format`	`png`, `jpeg`	Both formats are accepted. Use PNG to preserve transparency.
`background`	`opaque`, `transparent`	Set to `transparent` to request RGBA output with transparency.
`watermark`	`true`, `false`	Controls whether to add an AI-generated watermark.
`image`	Image URL	Source image for an editing request.

Size and input limits

The size options 1K, 1.5K, and 2K were accepted. Their returned dimensions were 1248x832, 1888x1248, and 2512x1680, respectively. The response includes the actual dimensions in data[].size. For image editing, pass a source image URL in image. See the official Seedream 5.5 overview and Seedream 5.5 announcement for model capabilities.

API Reference

View all Seedream 5.5 Pro workflows.

​Key capabilities

​Generate from text

​Edit or refine a reference image

​Generate a transparent image

​Output controls

​Size and input limits

API Reference

Key capabilities

Generate from text

Edit or refine a reference image

Generate a transparent image

Output controls

Size and input limits