Multistem Splitter API
Split one song into selected stems. The multistem splitter API can return vocals, drums, bass, piano, guitars, and a no_multistem remainder.
MP3 / WAV / AAC / OGG
Example: ["vocals","drum","bass"]
Default auto
deep_extraction or clear_cut
Optional
mp3, wav, flac, aac, or ogg
What you can build
Real workflows powered by this model.
Multistem splitter API for remix tools
Use the multistem splitter API to extract vocals, drums, bass, piano, and guitars for remix editors, loop libraries, musician practice apps, and creator workflows. Your app sends one source file and receives several labeled tracks. The multistem splitter API avoids separate calls for every stem. That keeps a song project easier to track when users need several parts at once. The multistem splitter API is a better fit than repeated single-stem jobs when the user expects a bundle.
Split stems
Multistem splitter API for several outputs
Send one source track and choose the stems your product needs. The multistem splitter API returns the selected stem tracks plus a no_multistem remainder when the task succeeds. This gives editors both the isolated parts and the source with those parts removed. A practice app can mute the selected parts, while an editor can drag each output into its own lane. The multistem splitter API keeps those outputs under one task id for project history.
Multistem splitter API with per-stem billing
Processing time and cost scale with selected stems. A one-minute song with vocals and drums selected counts as two stem minutes, billed at 200 credits ($0.20) per stem minute. The multistem splitter API surfaces that rule in both pricing and docs.
Pricing
Credit-based — 1 credit = $0.001 USD. Pay only for completed generations.
| Mode | Category | Unit | Price |
|---|---|---|---|
| Multistem split | |||
| Per selected stem | 1 stem minute | $0.2 200 credits | |
Why reAPI
Why this multistem splitter API uses stem_list
The multistem splitter API lets your product request multiple supported stems from one audio task. That is cleaner than asking users to run the same file over and over. It also keeps task history tied to one source track.
Labels for every returned file
Use output.tracks to map vocals, drum, bass, piano, electric_guitar, acoustic_guitar, and no_multistem labels to the right UI slots or storage paths. The multistem splitter API returns labels that are easier to handle than guessing from filenames, especially when several jobs finish at once. Keep that mapping in your database if users can reopen projects, rename exports, share bundles, compare versions, or download stems days later. This matters for teams with shared workspaces and exports.
Multistem splitter API stem-list guardrails
The playground validates stem_list before submission: 1 to 6 values, no unsupported stem names. The multistem splitter API docs show the same contract for backend calls. That prevents a common class of bad requests before they reach processing. Keep the same validation server-side so direct API callers get the same behavior.
Integrate the multistem splitter API in three steps
- step 01
Create an API key
Generate a reAPI key from workspace settings. Use it for backend calls to the audio generation endpoint.
Open - step 02
Submit a multistem task
POST model audio-multistem with a public audio_url and a stem_list array. Choose only the stems your product actually needs.
Open - step 03
Poll and map labels
GET /api/v1/tasks/:id until completed. Use output.audio_urls for downloads and output.tracks to map each selected stem and no_multistem.
Open
Frequently asked questions
Common questions about this model.
curl https://reapi.ai/api/v1/audio/generations \
-H "Authorization: Bearer $REAPI_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"audio-multistem","audio_url":"https://cdn.example.com/song.wav","stem_list":["vocals","drum","bass"],"encoder_format":"mp3"}'Ready to ship?
Try it in the playground or grab an API key to integrate now.