Stability AI Structure API

openapi: 3.2.0
info:
  title: Stability AI Stable Image Control Structure API
  description: The Stability AI Stable Image Control API provides image-to-image generation guided by structural inputs such as sketches, reference structures, and style guides. Using ControlNet-based models, developers can generate new images that follow the composition, edges, or layout of a source image while applying new styles or content based on text prompts. The API supports sketch-to-image, structure-guided generation, and style transfer workflows.
  version: v2beta
  contact:
    name: Stability AI Support
    url: https://platform.stability.ai
  termsOfService: https://stability.ai/terms-of-service
servers:
- url: https://api.stability.ai
  description: Production Server
security:
- bearerAuth: []
tags:
- name: Structure
  description: Generate images guided by the structural composition of a reference image, preserving edges and layout while applying new content from a text prompt.
paths:
  /v2beta/stable-image/control/structure:
    post:
      operationId: controlImageStructure
      summary: Generate an image guided by structural reference
      description: Generates a new image guided by the structural composition of a reference image. The reference image provides edge and layout information while the text prompt directs the content and style of the output. Useful for generating variations that maintain the same composition.
      tags:
      - Structure
      requestBody:
        required: true
        content:
          multipart/form-data:
            schema:
              $ref: '#/components/schemas/StructureControlRequest'
      responses:
        '200':
          description: Successfully generated structurally guided image
          content:
            image/jpeg:
              schema:
                type: string
                format: binary
            image/png:
              schema:
                type: string
                format: binary
            image/webp:
              schema:
                type: string
                format: binary
            application/json:
              schema:
                $ref: '#/components/schemas/ControlImageResponse'
        '400':
          description: Bad request due to invalid parameters
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '401':
          description: Unauthorized due to missing or invalid API key
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '403':
          description: Forbidden due to content moderation or insufficient permissions
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '429':
          description: Rate limit exceeded
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
components:
  schemas:
    ControlImageResponse:
      type: object
      properties:
        image:
          type: string
          description: Base64-encoded image data when Accept header is set to application/json.
        finish_reason:
          type: string
          enum:
          - SUCCESS
          - CONTENT_FILTERED
          description: The reason the generation finished.
        seed:
          type: integer
          description: The seed used for generation.
    ErrorResponse:
      type: object
      properties:
        id:
          type: string
          description: A unique identifier for the error instance.
        name:
          type: string
          description: The error type name.
        message:
          type: string
          description: A human-readable description of the error.
    StructureControlRequest:
      type: object
      required:
      - image
      - prompt
      properties:
        image:
          type: string
          format: binary
          description: The reference image to use for structural guidance. The edges and layout of this image will guide the output composition.
        prompt:
          type: string
          maxLength: 10000
          description: Text describing the desired output image content and style.
        negative_prompt:
          type: string
          maxLength: 10000
          description: Text describing elements to exclude from the output image.
        control_strength:
          type: number
          minimum: 0
          maximum: 1
          default: 0.7
          description: Controls how closely the output follows the reference structure. Higher values produce outputs more faithful to the reference layout.
        seed:
          type: integer
          minimum: 0
          maximum: 4294967294
          default: 0
          description: A value to control randomness in generation.
        output_format:
          type: string
          enum:
          - jpeg
          - png
          - webp
          default: png
          description: The output format of the generated image.
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      description: API key authentication. Pass your Stability AI API key as a Bearer token in the Authorization header.
externalDocs:
  description: Stability AI API Documentation
  url: https://platform.stability.ai/docs/api-reference