StemX

Stem separation, measured

Split vocals and instrumental from any song.

Free 60-second preview, no account required. Hear your stems before you spend a thing — then sign in to split the whole track.

Drag an audio file here

or

MP3, WAV, FLAC, M4A · up to 30 min

Vocal and instrumental separation, two ways

Two products, built on the same separation engine.

Stem separation

Drop a track and hear a free 60-second vocals-and-instrumental preview, right in your browser, before you spend anything. Sign in to split the full song.

Developer API

The same engine, live and key-gated, for automating separation in your own pipeline — a synchronous call for short clips, or an async job queue for anything longer.

Get an API key

Measured, not marketing

Two figures from this engine's own benchmark suite, reported as measured — not rounded up.

12.53×

realtime separation speed

Measured single-stream GPU inference throughput. Your own request also spends time queueing, encoding and uploading the result, so treat this as the engine's processing floor, not a promise about total wait.

11.43 / 14.15 dB

vocals / instrumental SI-SDR

Median scale-invariant SDR over a 12-track MUSDB18 sweep, comparing every separation model we hold a commercial licence to ship.

How we measured this →

Pricing

One tier you can use right now. Two more sized for when you need them.

Free

Available now

Free

30 minutes per month

1 concurrent job

Files kept 3 days

Create a free account

Pro

Coming soon

$12/month

500 minutes per month

2 concurrent jobs

Files kept 7 days

Vocals and instrumental together count as one minute.

Not yet purchasable — we haven't turned on payments for this tier. The Free tier above works today.

Scale

Coming soon

$49/month

3,000 minutes per month

4 concurrent jobs

Files kept 30 days

Vocals and instrumental together count as one minute.

Not yet purchasable — we haven't turned on payments for this tier. The Free tier above works today.

Ready to hear it split?

Drop a track above for a free, no-account preview — it only takes a few seconds to hear the difference.

Jump back to the upload box

Frequently asked questions

What do I get with the free preview?

A 60-second vocals-and-instrumental preview you can play right in your browser — no account, no card. Sign in only once you want the full track split and downloaded.

Why only vocals and instrumental, not more stems?

The commercial licence we ship under only covers UVR's MDX-NET vocals/instrumental weights. Every publicly available model that splits further — drums, bass, and the rest — is either research-only or has no commercial grant we could rely on. We'd rather offer two stems honestly than advertise stems we couldn't legally serve.

Is the Free plan actually free?

Yes — 30 minutes of separation a month, one job at a time, no card required. Sign up and it works today.

Can I get Pro or Scale today?

Not yet. We haven't turned on payments for the paid tiers, so there's nothing to buy right now — the pricing above shows what they'll include once they launch. The Free tier is fully usable in the meantime.

Is there a developer API?

Yes. It's live today, gated by an API key you create at /developers/keys, with a synchronous endpoint for short clips and an async job queue for longer ones.

How fast is the engine?

Our own benchmark measures 12.53× realtime for single-stream GPU inference — see the numbers above. A real request also spends time queueing, encoding and uploading, so your total wait will be lower than that figure.

Who built the separation models?

UVR (Anjok07 & aufr33) built the MDX-NET weights this API runs on, released under an MIT licence that requires crediting them — which we do in the footer on every page that uses the engine.