# ACE Step Audio Outpaint API

> Ka whakawhānui i tētahi topenga oro i mua i tōna tīmatanga, i muri rānei i tōna mutunga, mā te puoro hou kua tito

Ka haere tonu i tētahi ara ororongo i tukuna mā `audio_url`. Ka tāpiri a `extend_before_duration` me `extend_after_duration` kia 107 hēkona ia ki te tīmatanga, ki te mutunga rānei, ā, ko te taunoa he 30 hēkona i muri. Nō `tags` te kāhua, ā, ka taea te tuku `lyrics` mō ngā wāhanga tāpiri. He ōrite te tatau hipanga, te kaiwhakaraupapa me ngā tautuhinga arataki ki ērā atu tauira ACE Step.

- Model id: `ace-step/audio-outpaint`
- Made by: ACE Studio
- Category: Text to Music
- Output: audio
- Price per second of your output audio: $0.0002 / second of output audio (cheapest run $0.001 (1 API credit))
- Run: `POST https://api.doitong.com/v1/run/ace-step/audio-outpaint`
- Quote: `POST https://api.doitong.com/v1/quote/ace-step/audio-outpaint`
- Docs page: https://doitong.com/mi/developers/models/ace-step/audio-outpaint

## Pricing

Price: **$0.0002 / second of output audio**. Price per second of your output audio: 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 $0.006 = 6 API credits (30 s output audio × $0.0002).

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/ace-step/audio-outpaint` 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 |
|---|---|---|---|---|---|---|
| `audio_url` | `audio` | string (audio URL) | yes |  |  | URL kōnae ororongo mō te whakakī ā-waho. |
| `extend_before_duration` |  | number | no | `0` | 0 – 107 | Te roa o te toronga i mua i te tīmatanga o te ororongo, i roto i ngā hēkona. |
| `extend_after_duration` |  | number | no | `30` | 0 – 107 | Te roa o te toronga i muri i te mutunga o te ororongo, i roto i ngā hēkona. |
| `tags` |  | string | yes |  |  | Ngā tūtohu kāhua ororongo ka tukuna hei momo kua wehea ki ngā piko, ā, kei te wātea hoki a `prompt` hei ara kē mō te tuku. |
| `lyrics` |  | string | no | `` |  | Ngā kupu waiata, me ngā wāhanga waiata kua whakaritea mā ngā mana pērā i [verse], [chorus], me [bridge]. Mō te ororongo kāore he kupu waiata, waiho tēnei tāuru kia kore, tukuna rānei ko [inst] anake, ko [instrumental] rānei. |
| `number_of_steps` |  | integer | no | `27` | 3 – 60 | Te tatau hipanga e whakamahia ana i te whakaputanga ororongo. |
| `seed` |  | integer \| null | no |  |  | Te kākano mō te whakaputanga ka taea te tārua; ka kōwhiria matapōkeretia ki te kore koe e tuku uara. |
| `scheduler` |  | enum (string) | no | `euler` | `euler`, `heun` | Te kaiwhakarite e whakamahia ana i te whakaputanga. |
| `guidance_type` |  | enum (string) | no | `apg` | `cfg`, `apg`, `cfg_star` | Te momo CFG e whakamahia ana i te whakaputanga. |
| `granularity_scale` |  | integer | no | `10` | -100 – 100 | Te tauine tōnuitanga ka whakamahia i te whakaputanga. Mā te whakanui ake pea ka iti iho ngā paruparu. |
| `guidance_interval` |  | number | no | `0.5` | 0 – 1 | Te wāhanga o te hōtaka whakaputanga ka whiwhi aratohu: mā te kōwhiri i te 0.5 ka herea ki ngā hipanga mai i te 0.25 * infer_steps ki te 0.75 * infer_steps, kāore he aratohu i te tīmatanga me te mutunga. |
| `guidance_interval_decay` |  | number | no | `0` | 0 – 1 | Te hekenga o te aratohu i roto i te wā whakaputanga: mā te 0.0 ka noho whakakore te hekenga; ki te kore, ka heke te tauine i taua wā mai i guidance_scale ki min_guidance_scale. |
| `guidance_scale` |  | number | no | `15` | 0 – 200 | Te tauine o te aratohu ka whakamahia i te whakaputanga. |
| `minimum_guidance_scale` |  | number | no | `3` | 0 – 200 | Te tauine aratohu iti rawa ka tae atu i muri i te hekenga i te wā whakaputanga. |
| `tag_guidance_scale` |  | number | no | `5` | 0 – 10 | Te tauine o te aratohu tūtohu ka whakamahia i te whakaputanga. |
| `lyric_guidance_scale` |  | number | no | `1.5` | 0 – 10 | Te tauine o te aratohu kupu waiata ka whakamahia i te whakaputanga. |

File parameters (`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
{
  "tags": "lofi, hiphop, drum and bass, trap, chill",
  "audio": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
}
```

A fuller example:

```json
{
  "tags": "lofi, hiphop, drum and bass, trap, chill",
  "audio_url": "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/ace-step/audio-outpaint?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "tags": "lofi, hiphop, drum and bass, trap, chill",
    "audio_url": "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/ace-step/audio-outpaint?wait=20", {
  method: "POST",
  headers,
  body: JSON.stringify({
    "tags": "lofi, hiphop, drum and bass, trap, chill",
    "audio_url": "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 = {
    "tags": "lofi, hiphop, drum and bass, trap, chill",
    "audio_url": "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/ace-step/audio-outpaint", 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": "ace-step/audio-outpaint",
      "input": {
        "tags": "lofi, hiphop, drum and bass, trap, chill",
        "audio_url": "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": "ace-step/audio-outpaint",
  "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": 6,
    "usd": "0.006",
    "charged": 6,
    "refunded": 0
  },
  "input": {
    "tags": "lofi, hiphop, drum and bass, trap, chill",
    "audio_url": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
  },
  "output": {
    "audio": {
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.mp3",
      "content_type": "audio/mpeg",
      "file_name": "0-output.mp3",
      "file_size": 1843200
    },
    "seed": 42,
    "tags": "lofi, hiphop, drum and bass, trap, chill",
    "lyrics": "[inst]"
  },
  "outputs": [
    {
      "type": "audio",
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.mp3",
      "content_type": "audio/mpeg",
      "file_size": 1843200,
      "duration": 12,
      "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 |
|---|---|---|
| `audio` | object {url, content_type, file_name, file_size} | Te kōnae ororongo i whakaputaina. |
| `seed` | integer | Te kākano matapōkere i whakamahia i te whakaputanga. |
| `tags` | string | Ngā tūtohu momo waiata i whakamahia i te whakaputanga. |
| `lyrics` | string | Ngā kupu waiata i whakamahia i te whakaputanga. |

## Related models

- [ACE Step](https://doitong.com/developers/models/ace-step.md) (`ace-step`): $0.0002 / second
- [ACE Step Audio Inpaint](https://doitong.com/developers/models/ace-step/audio-inpaint.md) (`ace-step/audio-inpaint`): $0.0002 / second of input audio
- [ACE Step Audio To Audio](https://doitong.com/developers/models/ace-step/audio-to-audio.md) (`ace-step/audio-to-audio`): $0.0002 / second of input audio
- [ACE Step Prompt To Audio](https://doitong.com/developers/models/ace-step/prompt-to-audio.md) (`ace-step/prompt-to-audio`): $0.0002 / second
- [MiniMax Music 3](https://doitong.com/developers/models/minimax/music-3.md) (`minimax/music-3`): $0.002 / second
- [DiffRhythm: Lyrics to Song](https://doitong.com/developers/models/diffrhythm.md) (`diffrhythm`): $0.001 / second
- [Elevenlabs Music](https://doitong.com/developers/models/elevenlabs/music.md) (`elevenlabs/music`): $0.60 / minute of output audio
- [Elevenlabs Music v2](https://doitong.com/developers/models/elevenlabs/music/v2.md) (`elevenlabs/music/v2`): $0.60 / minute of output audio

## Links

- HTML page: https://doitong.com/developers/models/ace-step/audio-outpaint
- 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=ace-step/audio-outpaint
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.com/v1/models/ace-step/audio-outpaint