Add stem API

Updated 2026-09-18 · Suno-API team

Endpoint description

Add stem adds a specific instrument or track to an existing song — for example drums, bass, strings or a harmony track.

Endpoint: POST /api/music/add-stem

Billing: Paid, billed by the requested model; the amount actually charged follows the back-office price configuration.

Max Mode / Variety: this endpoint supports the optional parameters max_mode and variety (0-4). With max_mode on, this call is billed at 2× the price; variety costs nothing extra. What they mean and how to send them is in the "Advanced parameters" section of the New API overview.

Recommended model: suno-v6. suno-v6, suno-v6-wild and suno-v6-mini are available.

Wait times and timeouts (important): this is a synchronous endpoint — the order is only accepted and handed to generation when the response arrives. Measured, most requests return in 1-3 seconds, about 10% take longer than 30 seconds, and the longest is about 230 seconds. Set your client timeout to 300 seconds or more; no response does not mean nothing was generated, and do not retry immediately after a timeout (that duplicates the order and charges again). If the connection dropped, confirm later with GET /api/music/songs. See "Wait times and timeout settings" in the New API overview.

Authentication

Request parameters

Request example

curl -X POST https://www.suno-api.io/api/music/add-stem \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "suno-v6",
    "source_clip_id": "source_song_id",
    "stem_control_tags": "add Drums",
    "song_title": "Added drums",
    "wait_completion": false
  }'

Response

{
  "code": 200,
  "message": "success",
  "data": {
    "clips": [
      {
        "song_id": "result_song_id",
        "song_title": "Added drums",
        "status": "pending"
      },
      {
        "song_id": "result_song_id_2",
        "song_title": "Added drums",
        "status": "pending"
      }
    ]
  }
}

One call returns 2 results (billed as 2 songs); the example shows 2. Judge by the length of the clips array and do not hard-code a fixed count. Save clips[].song_id and poll the song query API until completed.

Notes

• stem_control_tags must be non-empty single-line text; it cannot contain line breaks or tabs and is limited to 120 characters.
• Add stem is not the same as separation: separation splits a song into vocals, backing or multi-track results — use the separation (vocal & backing split) API.