# suno-extend-music

> This API extends audio tracks while preserving the original style of the audio track. It includes Suno's upload functionality, allowing users to upload audio files for processing. The expected result is a longer track that seamlessly continues the input style.

## Overview

- **Endpoint**: `POST https://api.muapi.ai/api/v1/suno-extend-music`
- **Model ID**: `suno-extend-music`
- **Category**: text to audio
- **Variant**: Extend Music
- **Family**: suno
- **Cost**: 0.09 credits per call (some models compute cost dynamically based on params)

## API Usage

MuApi uses a **submit-then-poll** pattern: submit a job, get a `request_id`, then poll the predictions endpoint until `status` is `completed`. Optionally pass `?webhook=YOUR_URL` on the submit call to receive a POST callback when the job finishes (skip polling).

**Authentication**: send your MuApi key in the `x-api-key` header. Get one at https://muapi.ai/access-keys.

### 1. Submit a job

```http
POST https://api.muapi.ai/api/v1/suno-extend-music
Content-Type: application/json
x-api-key: YOUR_API_KEY
```

**Minimum (required only):**

```json
{
  "prompt": "<prompt>",
  "audio_url": "https://example.com/your-audio_url",
  "style": "<style>"
}
```

**Full example (all params):**

```json
{
  "prompt": "<prompt>",
  "audio_url": "https://example.com/your-audio_url",
  "style": "<style>",
  "model": "V5",
  "custom_mode": true,
  "title": "<title>",
  "persona_id": "<persona_id>",
  "persona_model": "style_persona",
  "continue_at": 1,
  "instrumental": true,
  "negative_tags": "<negative_tags>",
  "vocal_gender": "male",
  "style_weight": 0.65,
  "weirdness_constraint": 0.65,
  "audio_weight": 0.65
}
```

**Response:**

```json
{
  "request_id": "abc123",
  "status": "processing"
}
```

### 2. Poll for the result

```http
GET https://api.muapi.ai/api/v1/predictions/{request_id}/result
x-api-key: YOUR_API_KEY
```

Possible `status` values: `queued`, `pending`, `processing`, `completed`, `failed`, `cancelled`. Poll every 2-5 seconds until terminal. When `completed`, the result URLs are in the `outputs` array.

**Example response when `completed`:**

```json
{
  "id": "abc123",
  "status": "completed",
  "outputs": [
    "https://cdn.muapi.ai/.../output.png"
  ],
  "urls": {
    "get": "https://api.muapi.ai/api/v1/predictions/abc123/result"
  },
  "created_at": "2026-05-08T12:34:56Z",
  "has_nsfw_contents": []
}
```

### cURL

```bash
# 1. Submit
REQUEST_ID=$(curl -s -X POST https://api.muapi.ai/api/v1/suno-extend-music \
  -H "x-api-key: $MUAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"prompt":"<prompt>","audio_url":"https://example.com/your-audio_url","style":"<style>"}' | jq -r .request_id)

# 2. Poll until completed
while :; do
  RESP=$(curl -s https://api.muapi.ai/api/v1/predictions/$REQUEST_ID/result -H "x-api-key: $MUAPI_API_KEY")
  STATUS=$(echo "$RESP" | jq -r .status)
  [ "$STATUS" = "completed" ] && echo "$RESP" | jq .outputs && break
  [ "$STATUS" = "failed" ] && echo "$RESP" && exit 1
  sleep 3
done
```

### Python

```python
import os, time, requests

API = "https://api.muapi.ai/api/v1"
headers = {"x-api-key": os.environ["MUAPI_API_KEY"]}

r = requests.post(f"{API}/suno-extend-music", headers=headers, json={"prompt":"<prompt>","audio_url":"https://example.com/your-audio_url","style":"<style>"})
request_id = r.json()["request_id"]

while True:
    res = requests.get(f"{API}/predictions/{request_id}/result", headers=headers).json()
    if res["status"] == "completed":
        print(res["outputs"]); break
    if res["status"] == "failed":
        raise RuntimeError(res.get("error")); 
    time.sleep(3)
```

## Input Schema

The API accepts the following input parameters:

- **`prompt`** (`string`, _required_):
  A description of the desired audio content. The prompt will be strictly used as the lyrics and sung in the generated track. Maximum 3000 characters

- **`audio_url`** (`string`, _required_):
  The URL for uploading audio files. Ensure the uploaded audio does not exceed 2 minutes in length.

- **`style`** (`string`, _required_):
  Music style specification for the generated audio.

- **`model`** (`string`, _optional_):
  The AI model version to use for generation.
  - Default: `"V5"`
  - Options: `"V3_5"`, `"V4"`, `"V4_5"`, `"V4_5PLUS"`, `"V4_5ALL"`, `"V5"`, `"V5_5"`

- **`custom_mode`** (`boolean`, _optional_):
  Enable custom mode for advanced settings.
  - Default: `true`

- **`title`** (`string`, _optional_):
  Title for the generated music track (optional).

- **`persona_id`** (`string`, _optional_):
  Persona ID or custom voice ID to apply to the generated music (optional). Pair with persona_model to disambiguate.

- **`persona_model`** (`string`, _optional_):
  What kind of persona_id this is. Set to voice_persona when persona_id is a cloned voice ID from suno-voice-clone. Requires model V5 or V5_5.
  - Options: `"style_persona"`, `"voice_persona"`

- **`continue_at`** (`int`, _optional_):
  The time point (in seconds) from which to start extending the music. Value range: greater than 0 and less than the total duration of the uploaded audio. Specifies the position in the original track where the extension should begin.
  - Default: `1`

- **`instrumental`** (`boolean`, _optional_):
  Enable this option to generate music without prompt. If false prompt will used as the exact lyrics.
  - Default: `true`

- **`negative_tags`** (`string`, _optional_):
  Music styles or traits to exclude from the generated audio (optional). Use to avoid specific styles.

- **`vocal_gender`** (`string`, _optional_):
  Vocal gender preference for the singing voice (optional).
  - Default: `"male"`
  - Options: `"male"`, `"female"`

- **`style_weight`** (`int`, _optional_):
  Strength of adherence to the specified style (optional). Range 0–1, up to 2 decimal places.
  - Default: `0.65`

- **`weirdness_constraint`** (`int`, _optional_):
  Controls experimental/creative deviation (optional). Range 0–1, up to 2 decimal places.
  - Default: `0.65`

- **`audio_weight`** (`int`, _optional_):
  Balance weight for audio features vs. other factors (optional). Range 0–1, up to 2 decimal places.
  - Default: `0.65`

## Output Schema

The polling endpoint returns the following fields:

- **`id`** (`string`): The request ID.
- **`status`** (`string`): One of `queued`, `pending`, `processing`, `completed`, `failed`, `cancelled`.
- **`outputs`** (`array`): URLs to generated images/videos/audio. Empty until `status` is `completed`.
- **`urls.get`** (`string`): Self-link to re-fetch this prediction.
- **`error`** (`string` | `null`): Error message if `status` is `failed`.
- **`created_at`** (`string`): ISO-8601 timestamp of when the request was created.
- **`has_nsfw_contents`** (`array of boolean`): Per-output NSFW detection flags.

## Webhooks (optional)

Append `?webhook=https://your-server/path` to the submit URL. When the job reaches a terminal state, MuApi will POST the same shape as the polling response to your URL — no polling needed.

## Agent Integration

MuApi ships an MCP server and CLI so agents (Claude Code, Cursor, custom) can call this endpoint without writing HTTP code:

```bash
# Install the CLI
npm install -g muapi-cli

# Authenticate once
muapi auth login

# Expose all MuApi models as MCP tools to your agent
muapi mcp serve
```

The MCP server exposes tools that wrap submit + poll for every model, including `suno-extend-music`. See `muapi --help` for category-specific shortcuts (`muapi image generate`, `muapi video from-image`, etc.).

## Related Models
- [Boost Style](https://muapi.ai/playground/suno-boost-music-style)
- [Remix Music](https://muapi.ai/playground/suno-remix-music)
- [Extend Music](https://muapi.ai/playground/suno-extend-music)
- [Custom Voice Cloning](https://muapi.ai/playground/suno-voice-clone)
- [Add Vocals](https://muapi.ai/playground/suno-add-vocals)
- [Suno Sounds](https://muapi.ai/playground/suno-generate-sounds)
- [Suno Lyrics](https://muapi.ai/playground/suno-generate-lyrics)
- [Add Instrumental](https://muapi.ai/playground/suno-add-instrumental)
- [Create Music](https://muapi.ai/playground/suno-create-music)
- [Convert to WAV](https://muapi.ai/playground/suno-convert-to-wav)
- [Suno Mashup](https://muapi.ai/playground/suno-generate-mashup)

## Resources
- [Playground Page](https://muapi.ai/playground/suno-extend-music)
- [API Reference](https://muapi.ai/playground/suno-extend-music?tab=2)
- [Global llms.txt](https://muapi.ai/llms.txt)