Full disclosure up front: we make Tonekai, a local AI mastering app for macOS. We'll keep the comparison factual and tell you honestly when a cloud service is the better fit.
How each approach works
Cloud mastering runs on the provider's servers. You drag your mix into a browser (LANDR, for example, describes it as "just dragging & dropping your mix" — landr.com), the file uploads, their engine processes it, and you download the mastered version. The service typically charges per track or by subscription: LANDR lists single-track mastering at $10, with subscription tiers offering unlimited MP3 masters and WAV on higher plans (per the same page).
Local mastering runs on your own machine. The app analyzes and processes the file on your CPU — or on Apple Silicon Macs, with help from the Neural Engine. Nothing is uploaded; the audio never leaves your computer. Pricing is typically a one-time purchase, since there are no server costs to meter.
Same goal, two architectures. Here are the five differences that actually matter.
1. Where your unreleased music goes
With a cloud service, your pre-release track is transmitted to and processed on someone else's servers, under that provider's terms of service. Reputable providers handle this professionally — this isn't an accusation. But it is a real difference: an unreleased track is intellectual property, and some creators (and some labels' pre-release policies) simply prefer that masters never leave the building.
With local processing there's nothing to trust, because there's nothing transmitted. The file stays on your Mac from drop to export. If you work with unreleased or client material, this is the clearest argument for local.
2. Speed and iteration
Cloud mastering time is upload + queue + processing + download, and it scales with your connection and file size. A single pass is usually fine. The friction shows up when you iterate: master, listen, tweak the mix, re-master. Each round trip repeats the whole cycle.
Local mastering is bounded by your hardware. On Apple Silicon, analyzing and processing a full track takes seconds, and re-running after a mix tweak is just another drop. If your workflow is "bounce, check, adjust, repeat," local removes the loop's slowest step.
3. Offline use
Cloud mastering requires a connection — that's inherent to the architecture, not a flaw. Local mastering doesn't: on a train, on a plane, in a studio with bad Wi-Fi, it works identically. If you finish tracks on a laptop away from home, this one is worth weighing heavily.
4. Cost model
Neither model is universally cheaper; it depends on your volume. Per-track pricing (LANDR: $10/track for a one-off — source) suits people who release a single a quarter. Subscriptions suit steady high volume — if you keep paying. Stop subscribing, and the tap turns off.
One-time purchase apps front-load the cost: you pay once, then master as much as you want for as long as the app runs. For AI music creators generating dozens of tracks a month, the math tends to favor a flat one-time price quickly. Run your own numbers with your actual output.
5. Ecosystem and extras
Here's where cloud services earn real points. Mastering is often one piece of a larger platform — LANDR, for instance, also offers distribution, samples, and a mastering plugin for DAWs (landr.com). If you want one subscription that covers mastering plus distribution to streaming platforms, a cloud suite is legitimately convenient, and no local mastering app replaces that bundle.
Local apps do one thing. Whether that's a limitation or a feature depends on whether you wanted the rest of the bundle.
So which should you choose?
Choose a cloud service if: you're not on a Mac (or need it from any device), you want mastering bundled with distribution and other services, or you master so rarely that a single $10 track beats owning anything.
Choose a local app if: you work on a Mac, you iterate on masters more than once or twice per track, you care about unreleased audio staying on your machine, you work offline, or you'd rather pay once than subscribe.
There's no wrong answer here — there's a wrong answer for your workflow.
Where Tonekai fits
Tonekai is our take on the local option: drop an audio file on the app, it analyzes the track and adjusts loudness, balance and peaks automatically, and you A/B compare the original and mastered versions before exporting. It's Apple Silicon native, processes entirely on-device, and requires macOS 14 or later. Trying it is free; a one-time Pro Unlock (no subscription) adds WAV/AAC export and unlimited mastering.
Download Tonekai on the Mac App Store — free to try.
Frequently asked questions
Which sounds better, cloud or local? Neither architecture is inherently better-sounding — quality depends on the specific engine, not on where it runs. Both approaches offer free previews or trials, so the honest answer is: run the same track through both and A/B them with your own ears.
Does local processing drain my battery or slow my Mac? Processing a track takes seconds of compute on Apple Silicon, not sustained load. It's comparable to exporting a bounce from your DAW.
What happens to a cloud master if my connection drops mid-upload? You restart the upload. It's a minor annoyance rather than a dealbreaker — but it's also a step that simply doesn't exist locally.
The bottom line
Cloud and local mastering solve the same problem with opposite architectures. Cloud wins on device-independence and bundled ecosystems; local wins on privacy, iteration speed, offline use, and pay-once economics. Decide based on where you work, how often you master, and how you feel about unreleased tracks leaving your machine.