Describe it
Write a mood, add lyrics, and set tempo, key, and time signature. Up to ten minutes per Take.
Make music on your Mac, not in the cloud.
OpenLoop turns a prompt and lyrics into full tracks with open models running on Apple Silicon. Sketch ideas, compare Takes, and keep every file. No account, no upload, no credits.
Midnight Sketches
3 Takes
Engine
Model
Turbo
Idea
Lyrics
Takes
Duration
0:30
Takes per generation 2
Format
WAV
Takes
0:00 / 0:30
To repaint, play this Take and drag across the waveform to select a part.
Compare with
Take 2
Prompt
Settings
ModelACE-Step 1.5 Turbo
Duration0:30
Seed
Created
ProjectMidnight Sketches
Files
Interactive preview. Edit the prompt, generate Takes, compare A/B, or drag across the waveform to repaint. Audio is synthesized in your browser to show the workflow; it is not model output.
Built on open foundations
- ACE-Step 1.5
- MLX
- Swift 6
- SwiftUI
- uv
01 · Workflow
From one sentence to a keeper.
Every idea lives in a Project. Every generation becomes a Take you can play, compare, reproduce, and refine. It is a sketchbook, not a slot machine.
Compare Takes
Generate several Takes at once and flip between A and B at the same playhead position.
Reproduce or branch
Each Take records its seed and settings. Reproduce it exactly, or branch a related variation.
Repaint a region
Drag across the waveform to regenerate only that part. Loop it until it feels right.
02 · Private by design
Your studio never leaves your Mac.
Models download once. After that, every generation runs on Apple Silicon. Prompts, lyrics, and audio stay in a library that you own and can open in Finder.
0
prompts sent to a server
$0
no subscription or credits
10 min
maximum length per Take
On-device inference
A bundled runtime runs ACE-Step on MLX and Metal. Setup needs no Python install and no terminal.
A library you own
Projects, searchable History, and favorites. Export audio, timed lyrics, and metadata as plain files.
Open source
The app is AGPL-3.0. Read the code, build it yourself, and change what you need.
03 · For scripts and agents
The same studio, headless.
A separate CLI ships inside the app and shares the GUI library. A Take that a script generates appears in History at once, and the reverse is also true.
- Streams NDJSON v2 events for progress, results, and errors
- Sets up the runtime and models on first use
- Ctrl-C cancels cleanly and keeps completed Takes
$ CLI=/Applications/OpenLoop.app/Contents/MacOS/openloop-cli
$ "$CLI" run --configuration ace-step/turbo \
--prompt 'warm lo-fi piano, soft drums' --duration 30 --json
04 · Models
One app. Swappable engines.
A first-party catalog lists every Engine and Model Pack with its size, memory needs, and license. Install what fits your Mac, and switch without touching Settings files.
Model Pack
Configurations
Download
License
Status
ACE-Step 1.5 Standard
Lite · Turbo
11.46 GB
MIT
Available
ACE-Step 1.5 XL
XL Turbo
30.05 GB
MIT
Available
MiniMax Music 3 Turbo
—
—
Not yet verified
Announced
Requires Apple Silicon and macOS 15 or later. We recommend 24 GB of unified memory. Macs with less memory can run Lite, but may swap heavily.
05 · FAQ
Good questions.
Still curious? Open an issue on GitHub. The roadmap and known limits are public.
Is OpenLoop really free?
Yes. The app is open source under AGPL-3.0. There are no accounts, subscriptions, or generation credits. Your Mac does the work.
Does it need an internet connection?
Only for the first setup, which downloads the runtime and the Model Packs that you choose. Generation itself runs offline on your Mac.
Which Macs are supported?
Apple Silicon Macs on macOS 15 or later. 24 GB of unified memory is recommended. The current backend can exceed 16 GB even on Lite.
Can I release the music I generate?
Each model has its own license, which the app shows before installation. Generated content is not guaranteed to be free of copyright claims, so review the model and content terms before distribution.
Why does macOS warn me when I open it?
The Alpha is ad-hoc signed and not yet notarized. The release notes explain how to open it safely the first time.