Stability AI Generate Ultra API

openapi: 3.2.0
info:
  title: Stability AI Stable Image Generate Generate Ultra API
  description: The Stability AI Stable Image Generate API provides text-to-image generation capabilities powered by models including Stable Diffusion 3.5 and Stable Image Ultra. Developers can generate high-quality images from text prompts with control over style, dimensions, and output format. The API supports multiple model tiers including Stable Image Core for fast and affordable generation and Stable Image Ultra for state-of-the-art quality results.
  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: Generate Ultra
  description: Generate images using Stable Image Ultra, the highest quality model for state-of-the-art photorealistic and artistic image generation.
paths:
  /v2beta/stable-image/generate/ultra:
    post:
      operationId: generateImageUltra
      summary: Generate an image using Stable Image Ultra
      description: Generates a high-quality image from a text prompt using the Stable Image Ultra model. This endpoint produces state-of-the-art results with exceptional detail, lighting, and composition. Requests use multipart form data encoding.
      tags:
      - Generate Ultra
      requestBody:
        required: true
        content:
          multipart/form-data:
            schema:
              $ref: '#/components/schemas/GenerateUltraRequest'
      responses:
        '200':
          description: Successfully generated 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/GenerateImageResponse'
        '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:
    GenerateImageResponse:
      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. SUCCESS indicates a successful generation, CONTENT_FILTERED indicates the output was blocked by content moderation.
        seed:
          type: integer
          description: The seed used for generation. Useful for reproducing results.
    GenerateUltraRequest:
      type: object
      required:
      - prompt
      properties:
        prompt:
          type: string
          maxLength: 10000
          description: Text describing what you wish to see in the output image. Strong, descriptive prompts that clearly define elements, colors, and subjects lead to better results.
        negative_prompt:
          type: string
          maxLength: 10000
          description: Text describing elements to exclude from the output image.
        aspect_ratio:
          type: string
          enum:
          - '16:9'
          - '1:1'
          - '21:9'
          - '2:3'
          - '3:2'
          - '4:5'
          - '5:4'
          - '9:16'
          - '9:21'
          default: '1:1'
          description: Controls the aspect ratio of the generated image.
        seed:
          type: integer
          minimum: 0
          maximum: 4294967294
          default: 0
          description: A value to control randomness in generation. Set to 0 for a random seed. Using the same seed with the same parameters produces similar results.
        output_format:
          type: string
          enum:
          - jpeg
          - png
          - webp
          default: png
          description: The output format of the generated image.
    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.
  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