> ## Documentation Index > Fetch the complete documentation index at: https://docs.shuyou.ai/llms.txt > Use this file to discover all available pages before exploring further. # Veo 3.1 Fast Generate Preview > Create asynchronous video tasks with veo-3.1-fast-generate-preview via POST /v1/predictions. ## Overview Google **Veo 3.1 Fast Generate Preview** (`veo-3.1-fast-generate-preview`) supports: * **Text-to-video** — `prompt` only * **First / last frame** — `first_frame_url`, `last_frame_url` Faster generation than `veo-3.1-generate-preview` (no reference-image mode). ## Input parameters | Field | Required | Default | Notes | | ----------------- | -------- | ------- | -------------------------- | | `prompt` | Yes | — | Max **1000** characters | | `aspect_ratio` | No | `16:9` | `16:9` or `9:16` only | | `resolution` | No | `720P` | `720P`, `1080P`, `4K` | | `duration` | No | `8` | `4`, `6`, or `8` (seconds) | | `generate_audio` | No | `true` | Include generated audio | | `negative_prompt` | No | — | Negative guidance text | | `first_frame_url` | No | — | First keyframe image URL | | `last_frame_url` | No | — | Last keyframe image URL | ## OpenAPI ````yaml en/api-reference/video-series/google/veo-3.1-fast-generate-preview-generate.json POST /v1/predictions openapi: 3.1.0 info: title: Veo 3.1 Fast Generate Preview version: 1.0.0 servers: - url: https://api.shuyou.ai security: - bearerAuth: [] paths: /v1/predictions: post: tags: - Video Generation summary: Veo 3.1 Fast Generate Preview description: >- Google Veo 3.1 Fast Generate Preview (`veo-3.1-fast-generate-preview`) creates videos asynchronously via POST /v1/predictions. Supports text-to-video and first/last frame (faster generation). Poll [Get a prediction](/en/api-reference/task-management/get-prediction) using `data.task_id`, or configure top-level `webhook` for completion callbacks. operationId: createVeo31FastGeneratePreviewPrediction requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/Veo31FastGeneratePreviewPredictionRequest' examples: text_to_video: summary: Text to video value: model: veo-3.1-fast-generate-preview input: prompt: >- A cinematic shot of a majestic lion in the savannah at golden hour aspect_ratio: '16:9' resolution: 720P duration: 8 generate_audio: true text_to_video_minimal: summary: Minimal request value: model: veo-3.1-fast-generate-preview input: prompt: A cat playing on the grass first_last_frame: summary: First / last frame value: model: veo-3.1-fast-generate-preview input: prompt: Smooth transition between the two keyframes aspect_ratio: '16:9' resolution: 1080P duration: 6 first_frame_url: https://example.com/first-frame.png last_frame_url: https://example.com/last-frame.png webhook: https://api.shuyou.ai/backend/api/callback responses: '200': description: Async task created content: application/json: schema: $ref: '#/components/schemas/PredictionTaskResponse' example: data: task_id: 2c4d50261173430290971a2395a3b607 task_status: processing '400': description: Invalid request content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '402': description: Insufficient quota content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '403': description: Model access denied content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '429': description: Rate limit exceeded content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: Internal server error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' components: schemas: Veo31FastGeneratePreviewPredictionRequest: type: object required: - model - input properties: model: type: string description: Model ID. Use `veo-3.1-fast-generate-preview` for this endpoint. enum: - veo-3.1-fast-generate-preview default: veo-3.1-fast-generate-preview example: veo-3.1-fast-generate-preview input: $ref: '#/components/schemas/Veo31FastGeneratePreviewInput' webhook: type: string format: uri description: >- Optional HTTPS callback URL when the task completes, fails, or is cancelled. PredictionTaskResponse: type: object properties: data: type: object properties: task_id: type: string description: Async task ID. Use with Get a prediction or webhook correlation. example: 2c4d50261173430290971a2395a3b607 task_status: type: string description: Current task status, e.g. `processing`. example: processing required: - task_id - task_status required: - data ErrorResponse: type: object properties: error: type: object properties: code: type: string message: type: string type: type: string Veo31FastGeneratePreviewInput: type: object required: - prompt properties: prompt: type: string maxLength: 1000 description: The text prompt describing the video you want to generate. example: A cinematic shot of a majestic lion in the savannah at golden hour aspect_ratio: type: string description: >- The aspect ratio of the generated video. Only `16:9` and `9:16` are supported. enum: - '16:9' - '9:16' default: '16:9' example: '16:9' resolution: type: string description: The resolution of the generated video. enum: - 720P - 1080P - 4K default: 720P example: 720P duration: type: integer description: The duration of the generated video in seconds. enum: - 4 - 6 - 8 default: 8 example: 8 generate_audio: type: boolean description: Whether to generate audio for the video. default: true example: true negative_prompt: type: string description: A negative prompt to guide the video generation. first_frame_url: type: string format: uri description: URL of the first frame of the video. last_frame_url: type: string format: uri description: URL of the last frame of the video. additionalProperties: true securitySchemes: bearerAuth: type: http scheme: bearer description: '`Authorization: Bearer YOUR_API_KEY`' ````