> ## Documentation Index > Fetch the complete documentation index at: https://apixo.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # Seedance 2.0 Fast > ByteDance fast multimodal video generation with text-to-video, first-and-last-frames, and omni-reference modes ## Overview Seedance 2.0 Fast is a ByteDance video generation model for fast text-to-video, first-and-last-frame animation, and multimodal reference workflows. Use this page when you are ready to call the API after trying the model in the APIXO playground. | Capability | Value | | ---------------- | --------------------------------------------------------------------------------- | | Model ID | `seedance-2-0-fast` | | Modes | `text-to-video`, `first_and_last_frames`, `omni_reference` | | Prompt | Required, non-empty text | | Resolution | `480p`, `720p` | | Duration | 4-15 seconds, default `5` | | Aspect ratios | `auto`, `16:9`, `4:3`, `1:1`, `3:4`, `9:16`, `21:9` | | Reference images | `first_and_last_frames`: 1-2 images; `omni_reference`: 1-9 images | | Reference videos | `omni_reference` only, 1-3 videos, each 2-15 seconds, total up to 15 seconds | | Reference audio | `omni_reference` only, 1-3 audio files, each 2-15 seconds, total up to 15 seconds | | Audio and search | Optional generated audio and web search controls | ## Endpoint and authentication Base URL: ```text theme={null} https://api.apixo.ai/api/v1 ``` | Method | Endpoint | Purpose | | ------ | ----------------------------------------------- | ------------------------------------- | | `POST` | `/generateTask/seedance-2-0-fast` | Submit a generation task | | `GET` | `/statusTask/seedance-2-0-fast?taskId={taskId}` | Poll task status and retrieve results | All requests require your APIXO API key: ```http theme={null} Authorization: Bearer YOUR_API_KEY ``` Submit requests also require: ```http theme={null} Content-Type: application/json ``` ## Copy-paste async quickstart This minimal request submits a text-to-video task and returns a `taskId`. ```bash theme={null} curl -X POST "https://api.apixo.ai/api/v1/generateTask/seedance-2-0-fast" \ -H "Authorization: Bearer YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "request_type": "async", "input": { "mode": "text-to-video", "prompt": "a cinematic tracking shot through a rainy neon street", "resolution": "720p", "duration": 5, "aspect_ratio": "16:9", "sound": true, "web_search": false } }' ``` Successful response: ```json theme={null} { "code": 200, "message": "success", "data": { "taskId": "task_12345678" } } ``` Save the `taskId`; you need it to poll for the final result. ## Poll for result ```bash theme={null} curl -X GET "https://api.apixo.ai/api/v1/statusTask/seedance-2-0-fast?taskId=task_12345678" \ -H "Authorization: Bearer YOUR_API_KEY" ``` Processing response: ```json theme={null} { "code": 200, "message": "success", "data": { "taskId": "task_12345678", "state": "processing", "createTime": 1767965610929 } } ``` Success response: ```json theme={null} { "code": 200, "message": "success", "data": { "taskId": "task_12345678", "state": "success", "resultJson": "{\"resultUrls\":[\"https://file.apixo.ai/video.mp4\"]}", "createTime": 1767965610929, "completeTime": 1767965910929, "costTime": 300000 } } ``` Failed response: ```json theme={null} { "code": 200, "message": "success", "data": { "taskId": "task_12345678", "state": "failed", "failCode": "PromptInvalid", "failMsg": "Prompt is invalid or rejected by provider", "createTime": 1767965610929, "completeTime": 1767965620132 } } ``` Parse `resultJson` after `state` becomes `success`: ```javascript theme={null} const payload = JSON.parse(data.resultJson); const videoUrls = payload.resultUrls; ``` ## Request body ### Text-to-video ```json theme={null} { "request_type": "async", "input": { "mode": "text-to-video", "prompt": "a cinematic tracking shot through a rainy neon street", "resolution": "720p", "duration": 5, "aspect_ratio": "16:9", "sound": true, "web_search": false } } ``` ### First-and-last-frames ```json theme={null} { "request_type": "async", "input": { "mode": "first_and_last_frames", "prompt": "turn the still frames into a smooth cinematic camera move", "image_urls": [ "https://example.com/frame-start.png", "https://example.com/frame-end.png" ], "resolution": "720p", "duration": 5, "aspect_ratio": "9:16", "sound": true, "web_search": false } } ``` ### Omni-reference ```json theme={null} { "request_type": "async", "input": { "mode": "omni_reference", "prompt": "create a stylish product ad using the visual references and voice rhythm", "image_urls": [ "https://example.com/product-shot.png" ], "video_urls": [ "https://example.com/ref-motion.mp4" ], "audio_urls": [ "https://example.com/ref-audio.mp3" ], "resolution": "480p", "duration": 6, "aspect_ratio": "auto", "sound": true, "web_search": false } } ``` ## Parameters Result delivery mode. Use `async` for polling with `statusTask`, or `callback` for webhook delivery. Required when `request_type` is `callback`. Must be a public HTTPS URL that can receive the final task payload. See [Webhooks](/api-reference/webhooks). Seedance 2.0 Fast input parameters. Generation mode. Supported values: `text-to-video`, `first_and_last_frames`, `omni_reference`. Text prompt describing the desired video. The value is trimmed and must not be empty. Output resolution. Supported values: `480p`, `720p`. Output duration in seconds. Supports integers from `4` to `15`. Numeric strings are accepted and normalized, but integers are recommended. Output aspect ratio. Supported values: `auto`, `16:9`, `4:3`, `1:1`, `3:4`, `9:16`, `21:9`. Whether to generate audio with the output video. Enables web search so the provider can reference current information during generation. Reference image URLs. Required for `first_and_last_frames` with 1-2 images. Optional for `omni_reference` with 1-9 images. Reference video URLs for `omni_reference` mode only. When provided, supports 1-3 URLs. Each video must be 2-15 seconds, and total reference video duration cannot exceed 15 seconds. Reference audio URLs for `omni_reference` mode only. When provided, supports 1-3 URLs. Each audio file must be 2-15 seconds, and total reference audio duration cannot exceed 15 seconds. ### Mode-specific constraints * `text-to-video` uses the prompt and generation settings only. * `first_and_last_frames` requires `image_urls` with 1-2 images. The first image is the starting frame; the second image, when present, is the ending frame. * `omni_reference` can combine `image_urls`, `video_urls`, and `audio_urls`. * `omni_reference` requests with only `audio_urls`, and no images or videos, are rejected. * Reference media must be publicly reachable URLs so the API can fetch or probe them. ## Response format ### Submit task response `POST /generateTask/seedance-2-0-fast` returns a task ID when the task is accepted: API status code. `200` means the task was accepted. Human-readable status message. Unique task identifier used with the status endpoint. ### Status response fields Unique task identifier. Current task state: `pending`, `processing`, `success`, or `failed`. JSON string containing the generated video URLs in `resultUrls`. Present when `state` is `success`. Machine-readable failure code. Present when `state` is `failed`. Human-readable failure message. Present when `state` is `failed`. Task creation timestamp in Unix milliseconds. Task completion timestamp in Unix milliseconds. Present after completion. Processing duration in milliseconds. Present after successful completion or when available from the task log. ## Webhook callback mode Use callback mode when your backend should receive the final result automatically instead of polling. ```bash theme={null} curl -X POST "https://api.apixo.ai/api/v1/generateTask/seedance-2-0-fast" \ -H "Authorization: Bearer YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "request_type": "callback", "callback_url": "https://your-server.com/webhooks/apixo", "input": { "mode": "first_and_last_frames", "prompt": "turn the still frames into a smooth cinematic camera move", "image_urls": [ "https://example.com/frame-start.png", "https://example.com/frame-end.png" ], "resolution": "720p", "duration": 5, "aspect_ratio": "9:16", "sound": true, "web_search": false } }' ``` See [Webhooks](/api-reference/webhooks) for delivery requirements and retry behavior. ## Billing Seedance 2.0 Fast is billed per second. The selected `resolution` and whether `omni_reference` includes `video_urls` determine the unit price. | Configuration | APIXO price | | ------------------------------- | ----------------- | | `480p`, without video reference | `$0.076 / second` | | `480p`, with video reference | `$0.047 / second` | | `720p`, without video reference | `$0.156 / second` | | `720p`, with video reference | `$0.095 / second` | Billing formulas: * Without video reference: `output duration seconds x per-second rate` * With video reference: `(output duration seconds + total reference video seconds) x per-second rate` `text-to-video` and `first_and_last_frames` always use the "without video reference" rate. In `omni_reference` mode, "with video reference" applies only when `video_urls` is provided. Image and audio references do not add extra billable seconds. For current route and market comparison pricing, see [Pricing](https://apixo.ai/pricing). ## Latency and polling Actual latency may vary by prompt complexity, reference media, provider route, and current queue load. | Workflow | Typical generation time | Recommended first poll | Poll interval | | --------------------- | ----------------------- | ---------------------------- | ------------- | | Text-to-video | 3-6 minutes | 200-300s after task creation | 10-20s | | First-and-last-frames | 3-6 minutes | 200-300s after task creation | 10-20s | | Omni-reference | 3-6 minutes | 200-300s after task creation | 10-20s | For production workloads, use callback mode to reduce polling overhead during longer video tasks. No visible status change during the first few minutes can be normal for this model. Keep polling with backoff instead of immediately retrying the same task. Result URLs can be temporary. Download generated videos promptly after task completion. ## Errors and troubleshooting ### HTTP errors | Code | Meaning | What to do | | ----- | -------------------------------------------------------------------------------------- | ------------------------------------------------ | | `400` | Invalid request body, missing parameter, unsupported value, or invalid reference media | Fix the request before retrying | | `401` | Missing or invalid API key | Check the `Authorization` header | | `402` | Insufficient balance or quota | Add balance or switch account/key | | `403` | Key or route cannot access the model | Check permissions and route strategy | | `404` | Task not found | Check the `taskId` and model endpoint | | `429` | Rate limit or concurrency limit reached | Retry with exponential backoff | | `500` | Server error or unmapped provider failure | Retry with backoff | | `502` | Upstream provider error | Retry with backoff | | `504` | Upstream timeout | Retry or use callback mode for long-running jobs | ### Common request validation errors | Error | Meaning | What to do | | ---------------------------- | ----------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------- | | `Missing required parameter` | `input`, `mode`, `prompt`, or a mode-specific required field is missing | Add the required field | | `Invalid parameter type` | A field has the wrong JSON type | Use strings for text fields and URLs, booleans for `sound` and `web_search`, and integers for `duration` | | `Invalid parameter value` | A value is outside the supported set or range | Check `mode`, `resolution`, `duration`, `aspect_ratio`, and reference media durations | | `Param length exceeded` | Too many reference URLs were provided | Keep `image_urls`, `video_urls`, and `audio_urls` within the documented limits | | `ImageNotAccess` | A referenced URL could not be accessed | Use public, direct media URLs | ### Task failure codes | Fail code | Meaning | What to do | | ------------------ | -------------------------------------------- | ------------------------------------------------------- | | `PromptInvalid` | Prompt or input was rejected by the provider | Adjust the prompt or references | | `SensitiveContent` | Input or output was flagged by safety checks | Change the prompt or input media | | `RateLimited` | Provider or account rate limit was reached | Retry with exponential backoff | | `Timeout` | Provider timed out | Retry later or use callback mode | | `Unknown error` | Provider returned an unmapped failure | Retry with backoff or contact support with the `taskId` | See [Error Codes](/api-reference/errors) for the full error reference. ## Related links * [Generation API Overview](/models) * [Generate Task](/api-reference/generate-task) * [Status Task](/api-reference/status-task) * [Webhooks](/api-reference/webhooks) * [Error Codes](/api-reference/errors) * [Parameter Specification](/api-reference/parameters) * [Routing Strategies](/concepts/routing-strategies) * [Pricing](https://apixo.ai/pricing)