> ## Documentation Index
> Fetch the complete documentation index at: https://docs.modellix.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Seedream 4.0 I2I

> [Core Function] Seedream 4.0 I2I is an older generation image-to-image editing model. [Strengths] Maintained primarily for backward compatibility and stable API contracts. [Best For] Existing legacy integrations and workflows that strictly depend on this specific model version's quirks. [Limitations] Do NOT use this for new creations. It is a legacy model maintained for backward compatibility. [Routing] Only use if explicitly requested; otherwise use Seedream 5.0 Lite I2I.



## OpenAPI

````yaml /model-api/bytedance/bytedance-i2i.json post /bytedance/seedream-4.0-i2i
openapi: 3.1.0
info:
  description: The image-to-image models API from ByteDance.
  version: 1.0.0
  contact:
    name: Modellix Support
    email: support@modellix.ai
  title: ByteDance Image-to-Image Models API
servers:
  - url: https://api.modellix.ai/api/v1
    description: The image-to-image models API from ByteDance.
security:
  - bearerAuth: []
paths:
  /bytedance/seedream-4.0-i2i:
    post:
      summary: Seedream 4.0 I2I
      description: >-
        [Core Function] Seedream 4.0 I2I is an older generation image-to-image
        editing model. [Strengths] Maintained primarily for backward
        compatibility and stable API contracts. [Best For] Existing legacy
        integrations and workflows that strictly depend on this specific model
        version's quirks. [Limitations] Do NOT use this for new creations. It is
        a legacy model maintained for backward compatibility. [Routing] Only use
        if explicitly requested; otherwise use Seedream 5.0 Lite I2I.
      operationId: seedream40I2iAsync
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/Seedream40I2iRequest'
      responses:
        '200':
          description: Task submitted successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/AsyncTaskResponse'
components:
  schemas:
    Seedream40I2iRequest:
      type: object
      required:
        - prompt
        - image
      properties:
        prompt:
          type: string
          minLength: 1
          maxLength: 10000
          description: >-
            Description of the desired output. Maximum 10000 characters. We
            recommend keeping the prompt under 600 words. Excessively long
            prompts may scatter information, causing the model to overlook
            details and focus only on major elements, which can result in
            missing details in the generated image.
        image:
          type: array
          description: >-
            Input image array (1-14 images). Each image must be <= 10 MB.
            Supported formats: JPEG, PNG, WEBP, BMP, TIFF, GIF.
          minItems: 1
          maxItems: 14
          items:
            type: string
        size:
          type: string
          default: 2048x2048
          description: Output size in pixels.
        sequential_image_generation:
          type: string
          enum:
            - auto
            - disabled
          default: disabled
          description: Enable or disable sequential image generation.
        sequential_image_generation_max_images:
          type: integer
          default: 5
          minimum: 1
          maximum: 15
          description: Maximum number of images for sequential generation.
        optimize_prompt_mode:
          type: string
          enum:
            - standard
            - fast
          default: standard
          description: Mode for optimizing the input prompt.
    AsyncTaskResponse:
      type: object
      required:
        - code
        - message
        - data
      properties:
        code:
          type: integer
          description: Response code, 0 indicates success
          example: 0
        message:
          type: string
          description: Response message
          example: success
        data:
          type: object
          required:
            - status
            - task_id
            - model_id
          properties:
            status:
              type: string
              enum:
                - pending
                - processing
              description: Task status
              example: pending
            task_id:
              type: string
              description: Unique task identifier
              example: task-abc123
            model_id:
              type: string
              description: Model ID
              example: model-123
            get_result:
              type: object
              description: API information to query the task result
              properties:
                method:
                  type: string
                  description: HTTP method
                  example: GET
                url:
                  type: string
                  description: Full URL to query the task result
                  example: https://api.modellix.ai/api/v1/tasks/task-abc123
          description: Detailed data about the submitted asynchronous task.
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: 'API Key authentication. Format: `Bearer YOUR_API_KEY`.'

````