Music Generation API

Generate full-length music tracks with lyrics, instrumental, or custom style prompts.

Heads up: MiniMax generates a ~3 minute track per call regardless of duration hints. Generation takes 1-3 minutes. Set your client timeout to at least 200 seconds.

Endpoint

POST https://blockrun.ai/api/v1/audio/generations

Request

{
  "model": "minimax/music-2.5+",
  "prompt": "upbeat synthwave with warm neon pads and a driving beat",
  "instrumental": true,
  "duration_seconds": 30
}

Parameters

Parameter	Type	Required	Description
`model`	string	No	Model ID (default: `minimax/music-2.5+`)
`prompt`	string	Yes	Music style, mood, or description
`instrumental`	boolean	No	No vocals (default: false)
`lyrics`	string	No	Custom lyrics. Cannot combine with `instrumental: true`
`duration_seconds`	integer	No	Duration hint 5-240s (default: 30). Note: MiniMax ignores this — output is always ~3 min.

Available Models

Model ID	Price	Notes
`minimax/music-2.5+`	$0.1575	Latest flagship, best quality
`minimax/music-2.5`	$0.1575	Stable version

Response

{
  "created": 1775488202,
  "model": "minimax/music-2.5+",
  "data": [
    {
      "url": "https://cdn.minimax.io/music/...",
      "duration_seconds": 186
    }
  ]
}

Response Fields

Field	Type	Description
`created`	integer	Unix timestamp
`model`	string	Model used
`data[].url`	string	Time-limited CDN URL (expires ~24h). Download immediately.
`data[].duration_seconds`	integer	Actual duration of generated track
`data[].lyrics`	string	Generated lyrics (if not instrumental)

Examples

Via ClawRouter (recommended)

ClawRouter handles x402 payments automatically. Start it with openclaw gateway start, then call localhost:8402 directly.

curl -X POST http://localhost:8402/v1/audio/generations \
  -H "Content-Type: application/json" \
  -d '{
    "model": "minimax/music-2.5+",
    "prompt": "chill lo-fi hip hop, late night study vibes",
    "instrumental": true
  }'

Save the track:

URL=$(curl -s -X POST http://localhost:8402/v1/audio/generations \
  -H "Content-Type: application/json" \
  -d '{"model":"minimax/music-2.5+","prompt":"chill lo-fi hip hop","instrumental":true}' \
  | python3 -c "import sys,json; print(json.load(sys.stdin)['data'][0]['url'])")

curl -L "$URL" -o track.mp3

Direct API (Python)

import requests
from blockrun_llm.x402 import parse_payment_required, create_payment_payload
from blockrun_llm import load_wallet
from eth_account import Account

wallet_key = load_wallet()
account = Account.from_key(wallet_key)

# Step 1: get payment requirements
resp = requests.post(
    "https://blockrun.ai/api/v1/audio/generations",
    json={
        "model": "minimax/music-2.5+",
        "prompt": "epic orchestral film score, dramatic strings",
        "instrumental": True,
    },
)
pr = parse_payment_required(resp.headers["PAYMENT-REQUIRED"])
acc = pr["accepts"][0]

# Step 2: sign payment
payload = create_payment_payload(
    account=account,
    recipient=acc["payTo"],
    amount=str(acc["amount"]),
    network=acc["network"],
    resource_url=pr["resource"]["url"],
    resource_description="BlockRun music generation",
    max_timeout_seconds=acc["maxTimeoutSeconds"],
    extra=acc.get("extra"),
)

# Step 3: generate (takes 1-3 minutes)
result = requests.post(
    "https://blockrun.ai/api/v1/audio/generations",
    json={
        "model": "minimax/music-2.5+",
        "prompt": "epic orchestral film score, dramatic strings",
        "instrumental": True,
    },
    headers={"X-Payment": payload},
    timeout=200,
)

track = result.json()["data"][0]
print(f"Track URL: {track['url']}")
print(f"Duration: {track['duration_seconds']}s")
print(f"Tx: {result.headers['X-Payment-Receipt']}")

With Lyrics

result = requests.post(
    "https://blockrun.ai/api/v1/audio/generations",
    json={
        "model": "minimax/music-2.5+",
        "prompt": "upbeat pop with piano",
        "lyrics": "Sunshine in the morning\nBrightens up my day\nEvery step I'm taking\nLeads me on my way",
        "instrumental": False,
    },
    headers={"X-Payment": payload},
    timeout=200,
)

Pricing

Model	MiniMax Cost	BlockRun Price
minimax/music-2.5+	¥1.0 (~$0.138)	$0.1575
minimax/music-2.5	¥1.0 (~$0.138)	$0.1575

Prices include 5% BlockRun margin. Paid in USDC on Base network.

Limitations

Limitation	Detail
Output duration	Always ~3 minutes (MiniMax limitation)
Generation time	1-3 minutes per call
Format	MP3 only
Tracks per request	1
Duration control	Not supported (prompt hint ignored)
Image reference	Not supported

Error Codes

Code	Description
400	Invalid request (bad parameters or conflicting lyrics + instrumental)
402	Payment required or verification failed
429	Rate limit exceeded
504	Generation timed out (retry)
500	Server error

Prompt Tips

Describe the style clearly:

✅ "upbeat pop with piano and synth bass, energetic chorus"
✅ "dark ambient drone, slow evolving pads, cinematic tension"
✅ "jazz trio, upright bass, brushed snare, bebop swing"

Specify mood and tempo:

✅ "120 BPM, danceable, happy summer vibes"
✅ "slow and melancholic, solo piano, minor key"

For lyrics generation (no custom lyrics):

{
  "model": "minimax/music-2.5+",
  "prompt": "pop song about chasing dreams",
  "instrumental": false
}

MiniMax will auto-generate matching lyrics.