> ## 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. # Imagen 4.0 Ultra > [Core Function] Imagen 4.0 Ultra is Google's premium text-to-image model optimized for the highest quality and instruction alignment. [Strengths] It delivers ultimate photorealistic detail, superior texture rendering, and extremely strict adherence to complex, multi-part prompt instructions, supporting up to 2K resolution. [Best For] Highly recommended for high-end commercial marketing assets, professional design, intricate artistic compositions, and scenarios where precise instruction-following is paramount. [Limitations] Do NOT use this model if you need instant/real-time generation, native image editing (inpainting/outpainting), or negative prompts. It is the most expensive tier in the Imagen family. [Routing] Choose this model when the user demands the absolute highest quality, ultimate detail, or has highly complex prompt instructions. Otherwise, default to standard Imagen 4.0 or Imagen 4.0 Fast. ## OpenAPI ````yaml /model-api/google/google-t2i.json post /google/imagen-4.0-ultra-generate-001 openapi: 3.1.0 info: description: The text-to-image models API from Google (Gemini and Imagen series). version: 1.0.0 contact: name: Modellix Support email: support@modellix.ai title: Google Text-to-Image Models API servers: - url: https://api.modellix.ai/api/v1 description: The text-to-image models API from Google. security: - bearerAuth: [] paths: /google/imagen-4.0-ultra-generate-001: post: summary: Imagen 4.0 Ultra description: >- [Core Function] Imagen 4.0 Ultra is Google's premium text-to-image model optimized for the highest quality and instruction alignment. [Strengths] It delivers ultimate photorealistic detail, superior texture rendering, and extremely strict adherence to complex, multi-part prompt instructions, supporting up to 2K resolution. [Best For] Highly recommended for high-end commercial marketing assets, professional design, intricate artistic compositions, and scenarios where precise instruction-following is paramount. [Limitations] Do NOT use this model if you need instant/real-time generation, native image editing (inpainting/outpainting), or negative prompts. It is the most expensive tier in the Imagen family. [Routing] Choose this model when the user demands the absolute highest quality, ultimate detail, or has highly complex prompt instructions. Otherwise, default to standard Imagen 4.0 or Imagen 4.0 Fast. operationId: imagen40UltraGenerate001Async requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/ImagenStandardUltraRequest' examples: ultra_quality: summary: Ultra quality generation value: prompt: >- Cinematic still from a sci-fi film, astronaut on alien planet, volumetric lighting portrait: summary: Portrait with person generation value: prompt: >- Studio portrait of a professional businessperson, confident smile aspectRatio: '3:4' personGeneration: allow_adult imageSize: 2K responses: '200': description: Task submitted successfully content: application/json: schema: $ref: '#/components/schemas/AsyncTaskResponse' example: code: 0 message: success data: status: pending task_id: task-mno345 model_id: google/imagen-4.0-ultra-generate-001 get_result: method: GET url: https://api.modellix.ai/api/v1/tasks/task-mno345 '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '429': $ref: '#/components/responses/TooManyRequests' '500': $ref: '#/components/responses/InternalServerError' components: schemas: ImagenStandardUltraRequest: type: object required: - prompt properties: prompt: type: string description: Image description text minLength: 1 example: A golden retriever playing fetch on the beach at sunset sampleCount: type: integer description: Number of images to generate per request default: 1 minimum: 1 maximum: 4 example: 1 aspectRatio: type: string description: Image aspect ratio default: '1:1' enum: - '1:1' - '3:4' - '4:3' - '9:16' - '16:9' example: '16:9' personGeneration: type: string description: Person generation policy default: allow_all enum: - dont_allow - allow_adult - allow_all example: allow_all imageSize: type: string description: Output image resolution enum: - 1K - 2K example: 1K 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 for polling example: task-abc123 model_id: type: string description: Model ID in `provider/model` format example: google/nano-banana 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. ErrorResponse: type: object required: - code - message properties: code: type: integer description: Error code (equals HTTP status code) example: 400 message: type: string description: 'Error message in format ''Category: detail''' example: 'Invalid parameters: parameter ''prompt'' is required' responses: BadRequest: description: Invalid request parameters content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: code: 400 message: 'Invalid parameters: parameter ''prompt'' is required' Unauthorized: description: Unauthorized - Invalid or missing API Key content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: code: 401 message: 'Authentication failed: invalid API key' TooManyRequests: description: Too many requests - Rate limit exceeded headers: X-RateLimit-Limit: description: Maximum requests per minute schema: type: integer example: 100 X-RateLimit-Remaining: description: Remaining quota in current window schema: type: integer example: 0 X-RateLimit-Reset: description: Rate limit window reset time (Unix timestamp) schema: type: integer example: 1704067260 content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: code: 429 message: >- Rate limit exceeded: 100 requests per minute, retry after 60 seconds InternalServerError: description: Internal server error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: code: 500 message: Internal server error securitySchemes: bearerAuth: type: http scheme: bearer description: 'API Key authentication. Format: `Bearer YOUR_API_KEY`.' ````