Acestep AI Ace Step Audio Outpaint API | Pricing & Docs

acestep-ai/ace-step/audio-outpaint

Extend an audio track at the start, end, or both with style-matched continuations and optional lyrics, accessible on RunComfy models and HTTP API.

1. Get started

Use RunComfy's API to run acestep-ai/ace-step/audio-outpaint. For accepted inputs and outputs, see the model's schema.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/models/acestep-ai/ace-step/audio-outpaint \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "audio": "https://playgrounds-storage-public.runcomfy.net/tools/7357/media-files/input-example1.mp3",
    "tags": "lofi, hiphop, chill, mellow piano, soft drums"
  }'

2. Authentication

Set the YOUR_API_TOKEN environment variable with your API key (manage keys in your Profile) and include it on every request as a Bearer token via the Authorization header: Authorization: Bearer $YOUR_API_TOKEN.

3. API reference

Submit a request

Submit an asynchronous generation job and immediately receive a request_id plus URLs to check status, fetch results, and cancel.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/models/acestep-ai/ace-step/audio-outpaint \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "audio": "https://playgrounds-storage-public.runcomfy.net/tools/7357/media-files/input-example1.mp3",
    "tags": "lofi, hiphop, chill, mellow piano, soft drums"
  }'

Monitor request status

Fetch the current state for a request_id ("in_queue", "in_progress", "completed", or "cancelled").

curl --request GET \
  --url https://model-api.runcomfy.net/v1/requests/{request_id}/status \
  --header "Authorization: Bearer <token>"

Retrieve request results

Retrieve the final outputs and metadata for the given request_id; if the job is not complete, the response returns the current state so you can continue polling.

curl --request GET \
  --url https://model-api.runcomfy.net/v1/requests/{request_id}/result \
  --header "Authorization: Bearer <token>"

Cancel a request

Cancel a queued job by request_id; in-progress jobs cannot be cancelled.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/requests/{request_id}/cancel \
  --header "Authorization: Bearer <token>"

4. File inputs

Hosted file (URL)

Provide a publicly reachable HTTPS URL. Ensure the host allows server-side fetches (no login/cookies required) and isn't rate-limited or blocking bots. Recommended limits: images ≤ 50 MB (~4K), videos ≤ 100 MB (~2–5 min @ 720p). Prefer stable or pre-signed URLs for private assets.

5. Schema

Input schema

{
  "type": "object",
  "title": "Input schema",
  "required": [
    "audio",
    "tags"
  ],
  "properties": {
    "audio": {
      "title": "Audio",
      "description": "Source audio to extend. Provide an HTTPS URL to an MP3, WAV, or FLAC file (up to 60 minutes).",
      "type": "string",
      "default": "https://playgrounds-storage-public.runcomfy.net/tools/7357/media-files/input-example1.mp3"
    },
    "tags": {
      "title": "Tags",
      "description": "Comma-separated genre, mood, and instrument tags that steer the style of the generated extensions.",
      "type": "string",
      "default": "lofi, hiphop, chill, mellow piano, soft drums"
    },
    "extend_before_duration": {
      "title": "Extend Before Duration (seconds)",
      "description": "Seconds of new audio to generate before the original track. Set 0 to skip extending the start.",
      "type": "number",
      "minimum": 0,
      "maximum": 240,
      "default": 0
    },
    "extend_after_duration": {
      "title": "Extend After Duration (seconds)",
      "description": "Seconds of new audio to generate after the original track. Set 0 to skip extending the end.",
      "type": "number",
      "minimum": 0,
      "maximum": 240,
      "default": 30
    },
    "lyrics": {
      "title": "Lyrics",
      "description": "Optional lyrics to guide vocals in the extended sections. Leave blank to let the model write lyrics, or use [inst] / [instrumental] for no vocals.",
      "type": "string",
      "default": ""
    },
    "seed": {
      "title": "Seed",
      "description": "Random seed for reproducibility. Use -1 to randomize.",
      "type": "integer",
      "minimum": -1,
      "maximum": 2147483647,
      "default": -1
    }
  }
}

Output schema

{
  "output": {
    "type": "object",
    "properties": {
      "image": {
        "type": "string",
        "format": "uri",
        "description": "single image URL"
      },
      "video": {
        "type": "string",
        "format": "uri",
        "description": "single video URL"
      },
      "images": {
        "type": "array",
        "description": "multiple image URLs",
        "items": {
          "type": "string",
          "format": "uri"
        }
      },
      "videos": {
        "type": "array",
        "description": "multiple video URLs",
        "items": {
          "type": "string",
          "format": "uri"
        }
      }
    }
  }
}

RunComfy

RunComfy is the premier ComfyUI platform, offering ComfyUI online environment and services, along with ComfyUI workflows featuring stunning visuals. RunComfy also provides AI Models, enabling artists to harness the latest AI tools to create incredible art.

1. Get started

Use RunComfy's API to run acestep-ai/ace-step/audio-outpaint. For accepted inputs and outputs, see the model's schema.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/models/acestep-ai/ace-step/audio-outpaint \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "audio": "https://playgrounds-storage-public.runcomfy.net/tools/7357/media-files/input-example1.mp3",
    "tags": "lofi, hiphop, chill, mellow piano, soft drums"
  }'

3. API reference

Submit a request

Submit an asynchronous generation job and immediately receive a request_id plus URLs to check status, fetch results, and cancel.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/models/acestep-ai/ace-step/audio-outpaint \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "audio": "https://playgrounds-storage-public.runcomfy.net/tools/7357/media-files/input-example1.mp3",
    "tags": "lofi, hiphop, chill, mellow piano, soft drums"
  }'

Monitor request status

Fetch the current state for a request_id ("in_queue", "in_progress", "completed", or "cancelled").

curl --request GET \
  --url https://model-api.runcomfy.net/v1/requests/{request_id}/status \
  --header "Authorization: Bearer <token>"

Retrieve request results

Retrieve the final outputs and metadata for the given request_id; if the job is not complete, the response returns the current state so you can continue polling.

curl --request GET \
  --url https://model-api.runcomfy.net/v1/requests/{request_id}/result \
  --header "Authorization: Bearer <token>"

Cancel a request

Cancel a queued job by request_id; in-progress jobs cannot be cancelled.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/requests/{request_id}/cancel \
  --header "Authorization: Bearer <token>"

4. File inputs

Hosted file (URL)

5. Schema

Input schema

{
  "type": "object",
  "title": "Input schema",
  "required": [
    "audio",
    "tags"
  ],
  "properties": {
    "audio": {
      "title": "Audio",
      "description": "Source audio to extend. Provide an HTTPS URL to an MP3, WAV, or FLAC file (up to 60 minutes).",
      "type": "string",
      "default": "https://playgrounds-storage-public.runcomfy.net/tools/7357/media-files/input-example1.mp3"
    },
    "tags": {
      "title": "Tags",
      "description": "Comma-separated genre, mood, and instrument tags that steer the style of the generated extensions.",
      "type": "string",
      "default": "lofi, hiphop, chill, mellow piano, soft drums"
    },
    "extend_before_duration": {
      "title": "Extend Before Duration (seconds)",
      "description": "Seconds of new audio to generate before the original track. Set 0 to skip extending the start.",
      "type": "number",
      "minimum": 0,
      "maximum": 240,
      "default": 0
    },
    "extend_after_duration": {
      "title": "Extend After Duration (seconds)",
      "description": "Seconds of new audio to generate after the original track. Set 0 to skip extending the end.",
      "type": "number",
      "minimum": 0,
      "maximum": 240,
      "default": 30
    },
    "lyrics": {
      "title": "Lyrics",
      "description": "Optional lyrics to guide vocals in the extended sections. Leave blank to let the model write lyrics, or use [inst] / [instrumental] for no vocals.",
      "type": "string",
      "default": ""
    },
    "seed": {
      "title": "Seed",
      "description": "Random seed for reproducibility. Use -1 to randomize.",
      "type": "integer",
      "minimum": -1,
      "maximum": 2147483647,
      "default": -1
    }
  }
}

Output schema

{
  "output": {
    "type": "object",
    "properties": {
      "image": {
        "type": "string",
        "format": "uri",
        "description": "single image URL"
      },
      "video": {
        "type": "string",
        "format": "uri",
        "description": "single video URL"
      },
      "images": {
        "type": "array",
        "description": "multiple image URLs",
        "items": {
          "type": "string",
          "format": "uri"
        }
      },
      "videos": {
        "type": "array",
        "description": "multiple video URLs",
        "items": {
          "type": "string",
          "format": "uri"
        }
      }
    }
  }
}

Extend an audio track at the start, end, or both with style-matched continuations and optional lyrics, accessible on RunComfy models and HTTP API.

Table of contents

1. Get started

2. Authentication

3. API reference

Submit a request

Monitor request status

Retrieve request results

Cancel a request

4. File inputs

Hosted file (URL)

5. Schema

Input schema

Output schema

Extend an audio track at the start, end, or both with style-matched continuations and optional lyrics, accessible on RunComfy models and HTTP API.

Table of contents

1. Get started

2. Authentication

3. API reference

Submit a request

Monitor request status

Retrieve request results

Cancel a request

4. File inputs

Hosted file (URL)

5. Schema

Input schema

Output schema

Ace Step Audio Outpaint: Extend Tracks With Matching Style and Vocals on Models and API | RunComfy

Extend an audio track at the start, end, or both with style-matched continuations and optional lyrics, accessible on RunComfy models and HTTP API.

Table of contents

1. Get started

2. Authentication

3. API reference

Submit a request

Monitor request status

Retrieve request results

Cancel a request

4. File inputs

Hosted file (URL)

5. Schema

Input schema

Output schema

Ace Step Audio Outpaint: Extend Tracks With Matching Style and Vocals on Models and API | RunComfy

Extend an audio track at the start, end, or both with style-matched continuations and optional lyrics, accessible on RunComfy models and HTTP API.

Table of contents

1. Get started

2. Authentication

3. API reference

Submit a request

Monitor request status

Retrieve request results

Cancel a request

4. File inputs

Hosted file (URL)

5. Schema

Input schema

Output schema