# Sync Lipsync 3 API

> Re-times the lips of any talking video to a new audio track.

Sync Labs' lipsync-3 replaces the mouth movement of a person in a video so it matches a new voice track, for dubbing, ad localization and fixing lines in post. When the audio and video lengths differ, choose to cut, loop, bounce, pad with silence or remap.

- Model id: `sync-lipsync/v3`
- Made by: Sync Labs
- Category: Lipsync & Avatars
- Output: video
- Price per minute of your output video: $8.00 / minute of output video (cheapest run $8.00 (8000 API credits))
- Run: `POST https://api.doitong.com/v1/run/sync-lipsync/v3`
- Quote: `POST https://api.doitong.com/v1/quote/sync-lipsync/v3`
- Docs page: https://doitong.com/en-US/developers/models/sync-lipsync/v3

## Pricing

Price: **$8.00 / minute of output video**. Price per minute of your output video: the input files are measured before the run (length, resolution, frame rate). The quote measures the same files and is exactly what the run charges.

The full example input below costs $1.334 = 1334 API credits (0.1667 min output video × $8.00).

Prices are the upstream price in USD, paid from the API balance in API credits (1000 API credits = 1 USD). `POST https://api.doitong.com/v1/quote/sync-lipsync/v3` with the same JSON body returns the exact price for that input; the quote is exactly what a run charges. Invalid input is never charged and failed or canceled requests are refunded automatically.

## Input parameters

Send either the canonical name or the native field name (not both). Canonical names are the same across models.

| Parameter | Canonical name | Type | Required | Default | Allowed values / range | Description |
|---|---|---|---|---|---|---|
| `video_url` | `video` | string (video URL) | yes |  |  | URL pointing to the input video. |
| `audio_url` | `audio` | string (audio URL) | yes |  |  | Input audio location as a URL. |
| `sync_mode` |  | enum (string) | no | `cut_off` | `cut_off`, `loop`, `bounce`, `silence`, `remap` | Lip synchronization mode for handling differences in audio and video duration. |
| `options` |  | object {sync_mode, model_mode, prompt, temperature, active_speaker_detection, occlusion_detection_enabled} \| null | no |  |  | Configure additional Sync.so generation behavior here, with any supplied options.sync_mode taking precedence over the top-level sync_mode value. |
| `options.sync_mode` |  | enum (string) \| null | no |  | `cut_off`, `loop`, `bounce`, `silence`, `remap` | Override for the top-level sync_mode, specifying what happens when the input audio and video have different durations. |
| `options.model_mode` |  | enum (string) \| null | no |  | `lips`, `face`, `head`, `lipsync`, `emotion`, `talking_head` | Editing-area selection, mainly for react-1, specifying which region the model modifies. |
| `options.prompt` |  | enum (string) \| null | no |  | `happy`, `sad`, `angry`, `disgusted`, `surprised`, `neutral` | Emotion guidance used mainly by react-1 to steer generation. |
| `options.temperature` |  | number \| null | no |  | 0 – 1 | Expressiveness setting with no effect on sync-3, which manages this natively. For models that use this setting, 0 gives the least expressive lipsync and 1 gives the most. |
| `options.active_speaker_detection` |  | object {auto_detect, v3, use_v2, frame_number, coordinates, bounding_boxes, bounding_boxes_url, face_image} \| null | no |  |  | Settings for identifying the active speaker in videos containing multiple people. |
| `options.active_speaker_detection.auto_detect` |  | boolean \| null | no |  |  | Automatic identification of the active speaker and application of generation to that person. |
| `options.active_speaker_detection.v3` |  | boolean \| null | no |  |  | Use of v3 active-speaker detection. |
| `options.active_speaker_detection.use_v2` |  | boolean \| null | no |  |  | Deprecated setting for v2 active-speaker detection. |
| `options.active_speaker_detection.frame_number` |  | integer \| null | no |  | ≥ 0 | Index of the frame used for coordinates that manually select the speaker. |
| `options.active_speaker_detection.coordinates` |  | array of integer \| null | no |  | 2 – 2 items | Facial reference point given as [x, y] for the speaker in frame_number. |
| `options.active_speaker_detection.bounding_boxes` |  | array of array of integer \| null | no |  |  | Detected face bounding boxes for each frame, expressed as [x1, y1, x2, y2]. |
| `options.active_speaker_detection.bounding_boxes_url` |  | string \| null | no |  |  | JSON file URL providing bounding boxes for each frame. |
| `options.active_speaker_detection.face_image` |  | string \| null | no |  |  | Face image encoded in Base64, used to select the speaker manually. |
| `options.occlusion_detection_enabled` |  | boolean \| null | no |  |  | Occlusion-detection toggle with no effect on sync-3 because detection is automatic there; otherwise, it controls whether generation includes occlusion detection. |

File parameters (`video`, `audio`) take a public `https://` URL, a `data:` URI up to 10 MB, or the `file_url` of an upload from `POST /files`.

## Example input

Required parameters only:

```json
{
  "video": "https://content.doitong.com/video/showcase/v3/avatar/talking_avatar_loop.mp4",
  "audio": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
}
```

A fuller example:

```json
{
  "video": "https://content.doitong.com/video/showcase/v3/avatar/talking_avatar_loop.mp4",
  "audio": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
}
```

## Run it

Set `DOITONG_API_KEY` to a key from https://doitong.com/developers/dashboard#keys. `?wait=20` returns the finished request in the same call when it is ready within 20 seconds; otherwise poll `GET /requests/{id}` (it also accepts `?wait=`), or pass `webhook_url`.

### curl

```bash
# Run the model; wait up to 20 s for the finished result in the same call
curl -X POST "https://api.doitong.com/v1/run/sync-lipsync/v3?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "video": "https://content.doitong.com/video/showcase/v3/avatar/talking_avatar_loop.mp4",
    "audio": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
  }'

# Still "queued" or "running"? Poll with the id from the response:
curl "https://api.doitong.com/v1/requests/REQUEST_ID?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY"
```

### JavaScript

```javascript
const API = "https://api.doitong.com/v1";
const headers = {
  "Authorization": "Bearer " + process.env.DOITONG_API_KEY,
  "Content-Type": "application/json",
};

// Run the model; wait up to 20 s for the finished result in the same call
let res = await fetch(API + "/run/sync-lipsync/v3?wait=20", {
  method: "POST",
  headers,
  body: JSON.stringify({
    "video": "https://content.doitong.com/video/showcase/v3/avatar/talking_avatar_loop.mp4",
    "audio": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
  }),
});
let request = await res.json();
if (!res.ok) throw new Error(request.error.code + ": " + request.error.message);

// Not finished yet: long-poll until it is
while (request.status === "queued" || request.status === "running") {
  res = await fetch(API + "/requests/" + request.id + "?wait=20", { headers });
  request = await res.json();
}
if (request.status !== "succeeded") throw new Error(JSON.stringify(request.error));
console.log(request.outputs.map((o) => o.url), request.cost.credits + " API credits ($" + request.cost.usd + ")");
```

### Python

```python
import os
import requests

API = "https://api.doitong.com/v1"
headers = {"Authorization": "Bearer " + os.environ["DOITONG_API_KEY"]}

payload = {
    "video": "https://content.doitong.com/video/showcase/v3/avatar/talking_avatar_loop.mp4",
    "audio": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3",
}

# Run the model; wait up to 20 s for the finished result in the same call
r = requests.post(API + "/run/sync-lipsync/v3", params={"wait": 20}, json=payload, headers=headers)
request = r.json()
if not r.ok:
    raise RuntimeError(request["error"]["code"] + ": " + request["error"]["message"])

# Not finished yet: long-poll until it is
while request["status"] in ("queued", "running"):
    request = requests.get(API + "/requests/" + request["id"], params={"wait": 20}, headers=headers).json()
if request["status"] != "succeeded":
    raise RuntimeError(request["error"])
print([o["url"] for o in request["outputs"]], request["cost"]["credits"], "API credits", "$" + request["cost"]["usd"])
```

### MCP

The MCP server at `https://api.doitong.com/v1/mcp` exposes the tools `search_models`, `get_model`, `quote`, `run`, `get_request`, `cancel_request`, `list_requests`, `create_upload` and `get_account`. A `run` call for this model:

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "run",
    "arguments": {
      "model_id": "sync-lipsync/v3",
      "input": {
        "video": "https://content.doitong.com/video/showcase/v3/avatar/talking_avatar_loop.mp4",
        "audio": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
      },
      "wait_seconds": 20
    }
  }
}
```

## Response

Every call returns a request object. `status` is one of `queued`, `running`, `succeeded`, `failed`, `canceled`. `outputs` lists the generated files with URLs on our storage (kept forever, or 7 days with `?storage=temporary`; `storage` says which); `output` is the model's own result object with the same URLs.

```json
{
  "id": "req_8k2m4q7x1z9c3v5b6n0p2r4t",
  "object": "request",
  "model": "sync-lipsync/v3",
  "status": "succeeded",
  "created_at": "2026-10-20T12:00:00Z",
  "started_at": "2026-10-20T12:00:02Z",
  "completed_at": "2026-10-20T12:00:09Z",
  "queue_position": null,
  "cost": {
    "credits": 1334,
    "usd": "1.334",
    "charged": 1334,
    "refunded": 0
  },
  "input": {
    "video": "https://content.doitong.com/video/showcase/v3/avatar/talking_avatar_loop.mp4",
    "audio": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
  },
  "output": {
    "video": {
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.mp4",
      "content_type": "video/mp4",
      "file_name": "0-output.mp4",
      "file_size": 1843200
    }
  },
  "outputs": [
    {
      "type": "video",
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.mp4",
      "content_type": "video/mp4",
      "file_size": 1843200,
      "width": 1280,
      "height": 720,
      "duration": 5,
      "stored": true
    }
  ],
  "error": null,
  "metrics": {
    "inference_seconds": 6.8
  },
  "urls": {
    "self": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t",
    "cancel": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t/cancel"
  }
}
```

### Output fields (`output`)

| Field | Type | Description |
|---|---|---|
| `video` | object {url, content_type, file_name, file_size} | Video produced by the model. |

## Related models

- [Sync React-1](https://doitong.com/developers/models/sync-lipsync/react-1.md) (`sync-lipsync/react-1`): $10.00 / minute of output video
- [sync-3 Avatar Image to Video](https://doitong.com/developers/models/sync-lipsync/v3/image-to-video.md) (`sync-lipsync/v3/image-to-video`): $8.00 / minute of input audio
- [Kling AI Avatar 2.0 Pro](https://doitong.com/developers/models/kling-video/ai-avatar/v2/pro.md) (`kling-video/ai-avatar/v2/pro`): $0.115 / second of input audio
- [VEED Fabric 1.0](https://doitong.com/developers/models/veed/fabric-1.0.md) (`veed/fabric-1.0`): from $0.08 / second of input audio
- [Sync Lipsync](https://doitong.com/developers/models/sync-lipsync/v2/pro.md) (`sync-lipsync/v2/pro`): $5.00 / minute of output video
- [Sync Lipsync 2.0](https://doitong.com/developers/models/sync-lipsync/v2.md) (`sync-lipsync/v2`): from $3.00 / minute of output video
- [sync.so -- lipsync 1.9.0-beta](https://doitong.com/developers/models/sync-lipsync.md) (`sync-lipsync`): $0.70 / minute of output video
- [AI Avatar Multi](https://doitong.com/developers/models/ai-avatar/multi.md) (`ai-avatar/multi`): from $0.20 / second of output video

## Links

- HTML page: https://doitong.com/developers/models/sync-lipsync/v3
- All models and guides for AI agents: https://doitong.com/developers/llms.txt
- OpenAPI 3.1 with this model's typed request body: https://doitong.com/developers/openapi.json?model=sync-lipsync/v3
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.com/v1/models/sync-lipsync/v3