> ## Documentation Index > Fetch the complete documentation index at: https://evolink.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # Seedream 5.5 Image Generation > > 🚧 **This model is not yet available, stay tuned** - Seedream 5.5 (doubao-seedream-5.5) supports text-to-image, image-to-image and image editing, including transparent backgrounds - Processing is asynchronous. Use the returned task ID to [query task status](/en/api-manual/task-management/get-task-detail) - Generated image links are valid for 24 hours; save them promptly ### Billing - Charges are based on the actual number of generated images - Reference images are charged separately from generated images ## OpenAPI ````yaml en/api-manual/image-series/seedream-5.5/seedream-5.5-image-generate.json POST /v1/images/generations openapi: 3.1.0 info: title: doubao-seedream-5.5 Interface description: >- Create image tasks using AI models, supporting multiple models and parameter configurations license: name: MIT version: 1.0.0 servers: - url: https://api.evolink.ai description: Production environment security: - bearerAuth: [] tags: - name: Image Generation description: AI image generation related APIs paths: /v1/images/generations: post: tags: - Image Generation summary: doubao-seedream-5.5 Interface description: >- > 🚧 **This model is not yet available, stay tuned** - Seedream 5.5 (doubao-seedream-5.5) supports text-to-image, image-to-image and image editing, including transparent backgrounds - Processing is asynchronous. Use the returned task ID to [query task status](/en/api-manual/task-management/get-task-detail) - Generated image links are valid for 24 hours; save them promptly ### Billing - Charges are based on the actual number of generated images - Reference images are charged separately from generated images operationId: createImageGeneration requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/ImageGenerationRequest' examples: text_to_image: summary: Text to Image value: model: doubao-seedream-5.5 prompt: A serene lake reflecting the beautiful sunset size: '16:9' quality: 2K transparent_text_to_image: summary: Text-to-image with a transparent background value: model: doubao-seedream-5.5 prompt: >- A cartoon sticker of an orange kitten, transparent background size: '1:1' quality: 1K background: transparent responses: '200': description: Image generation task created successfully content: application/json: schema: $ref: '#/components/schemas/ImageGenerationResponse' '400': description: Invalid request parameters content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: code: invalid_request message: Invalid request parameters type: invalid_request_error '401': description: Unauthenticated, invalid or expired token content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: code: unauthorized message: Invalid or expired token type: authentication_error '402': description: Insufficient quota, recharge required content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: code: insufficient_quota message: Insufficient quota. Please top up your account. type: insufficient_quota '403': description: Access denied content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: code: model_access_denied message: 'Token does not have access to model: doubao-seedream-5.5' type: invalid_request_error '429': description: Rate limit exceeded content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: code: rate_limit_exceeded message: Too many requests, please try again later type: rate_limit_error '500': description: Internal server error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: code: internal_error message: Internal server error type: api_error components: schemas: ImageGenerationRequest: type: object required: - model - prompt properties: model: type: string description: Image generation model name enum: - doubao-seedream-5.5 default: doubao-seedream-5.5 example: doubao-seedream-5.5 prompt: type: string description: >- Prompt describing the image you want to generate, or describing how to edit the input image **Language support:** In addition to Chinese and English, Seedream 5.5 also supports Russian, Arabic, Filipino, Thai, Turkish, Korean, Malay, Spanish, Portuguese, Indonesian, French, German, Vietnamese and Japanese. **Length limit:** Up to `4000` tokens (about 2,600 Chinese characters or 5,000 English words); exceeding it returns `400` and is not billed. **Recommendation:** Keep prompts under 300 Chinese characters or 600 English words. A longer prompt still fits the limit but dilutes the information, and the model may miss details, leaving elements out of the image. example: A serene lake reflecting the beautiful sunset size: type: string description: >- Size of generated image, supports two formats: **Method 1 - Ratio format:** - `auto`, `1:1`, `2:3`, `3:2`, `3:4`, `4:3`, `4:5`, `5:4`, `9:16`, `16:9`, `21:9`, `9:21` - Works with the `quality` parameter to automatically generate an image at the corresponding aspect ratio and resolution, without manually specifying pixels **Method 2 - Pixel format:** - Width x height, e.g.: `1024x1024`, `2048x2048` - Total pixel range: `[921600, 4624220]` - Aspect ratio range: `[1/16, 16]` - Both width and height must be greater than `14px` Defaults to `auto` when `size` is omitted. The model determines the aspect ratio from the prompt, and `quality` sets the output resolution. default: auto example: '16:9' quality: type: string description: >- Output resolution, used with the aspect ratio format of `size`. Defaults to `1K`. | Aspect ratio | 1K | 1.5K | 2K | |---|---|---|---| | `1:1` | 1024×1024 | 1536×1536 | 2048×2048 | | `2:3` | 832×1248 | 1248×1872 | 1664×2496 | | `3:2` | 1248×832 | 1872×1248 | 2496×1664 | | `3:4` | 864×1152 | 1344×1792 | 1776×2368 | | `4:3` | 1152×864 | 1792×1344 | 2368×1776 | | `4:5` | 896×1120 | 1344×1680 | 1792×2240 | | `5:4` | 1120×896 | 1680×1344 | 2240×1792 | | `9:16` | 800×1424 | 1152×2048 | 1584×2816 | | `16:9` | 1424×800 | 2048×1152 | 2816×1584 | | `21:9` | 1568×672 | 2352×1008 | 3136×1344 | | `9:21` | 672×1568 | 1008×2352 | 1344×3136 | enum: - 1K - 1.5K - 2K default: 1K example: 2K prompt_priority: type: string description: >- Prompt optimization mode. Only `standard` is supported and is the default. Passing `fast` returns `400` with no charge. enum: - standard default: standard example: standard image_urls: type: array description: >- Reference image URL list for image-to-image and image editing features **Note:** - Reference images are charged separately from generated images - Single request supports input image quantity: `10` images - Image size: no more than `30MB` - Supported image formats: `.jpeg`, `.jpg`, `.png`, `.webp`, `.bmp`, `.tiff`, `.gif`, `.heic`, `.heif` - Aspect ratio (width/height) range: `[1/16, 16]` - Width and height (px) > 14 - Total pixels: `[196, 6000×6000]` - Image URLs must be directly viewable by the server, or the image URL should trigger direct download when accessed (typically these URLs end with image file extensions, such as `.png`, `.jpg`) items: type: string format: uri maxItems: 10 example: - https://example.com/image1.png - https://example.com/image2.png output_format: type: string description: >- Output image format **Options:** - `png`: PNG format (default) - `jpeg`: JPEG format **Note:** With `background=transparent`, output is always png: omitting `output_format` automatically produces png, while specifying `jpeg` is rejected. enum: - png - jpeg default: png example: png watermark: type: boolean description: Whether to add a watermark to the generated image default: false example: false background: type: string description: >- Output background type. Defaults to `auto`. **Options:** - `auto`: The model determines the background from the prompt and reference images. `result_data[].background` in the task detail returns the actual type: `transparent` or `opaque` - `transparent`: Generate a PNG image with an alpha channel. Supported for both text-to-image and image-to-image - `opaque`: Generate an image with an opaque background **When using `transparent`:** - Reference images are optional. If provided, up to `10` are supported and they do not need an alpha channel - Output must be `png`. Omitting `output_format` uses `png` automatically; passing `jpeg` returns an error enum: - auto - transparent - opaque default: auto example: auto callback_url: type: string description: >- HTTPS callback address after task completion **Callback Timing:** - Triggered when task is completed, failed, or cancelled - Sent after billing confirmation is completed **Security Restrictions:** - Only HTTPS protocol is supported - Callback to internal IP addresses is prohibited (127.0.0.1, 10.x.x.x, 172.16-31.x.x, 192.168.x.x, etc.) - URL length must not exceed `2048` characters **Callback Mechanism:** - Timeout: `10` seconds - Maximum `3` retries on failure (retries after `1` second/`2` seconds/`4` seconds) - Callback response body format is consistent with the task query API response format - Callback address returning 2xx status code is considered successful, other status codes will trigger retry format: uri example: https://your-domain.com/webhooks/image-task-completed ImageGenerationResponse: type: object properties: created: type: integer description: Task creation timestamp example: 1757165031 id: type: string description: Task ID example: task-unified-1793612886-seedream55 model: type: string description: Actual model name used example: doubao-seedream-5.5 object: type: string enum: - image.generation.task description: Specific task type progress: type: integer description: Task progress percentage (0-100) minimum: 0 maximum: 100 example: 0 status: type: string description: Task status enum: - pending - processing - completed - failed example: pending task_info: $ref: '#/components/schemas/TaskInfo' description: Async task information type: type: string enum: - text - image - audio - video description: Task output type example: image usage: $ref: '#/components/schemas/Usage' description: Usage and billing information ErrorResponse: type: object properties: error: type: object properties: code: type: string description: Error code identifier message: type: string description: Error description type: type: string description: Error type TaskInfo: type: object properties: can_cancel: type: boolean description: Whether the task can be cancelled example: true estimated_time: type: integer description: Estimated completion time (seconds) minimum: 0 example: 45 Usage: type: object description: Usage and billing information properties: billing_rule: type: string description: Billing rule enum: - per_call - per_image - per_token - per_second example: per_image credits_reserved: type: number description: Estimated credits consumed minimum: 0 example: 1.836 user_group: type: string description: User group category example: default securitySchemes: bearerAuth: type: http scheme: bearer description: >- ##All APIs require Bearer Token authentication## **Get API Key:** Visit [API Key Management Page](https://evolink.ai/dashboard/keys) to get your API Key **Add to request header:** ``` Authorization: Bearer YOUR_API_KEY ``` ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.