SpacesSync
Beta · invite only
Multi-monitor Spaces, finally working.
Every Space switch on a multi-monitor Mac leaves half your workspace behind. SpacesSync ends that. Switch on one display, the others follow. Works with native macOS Spaces, doesn't rearrange your windows. Two-minute setup.
All your monitors on the same Space.
Free during beta.
$12.99 when 1.0 ships. Perpetual license, 3 Macs, 14-day refund.
We'll invite you to the beta if there's room, otherwise notify you when 1.0 ships. One email per real event — no drip.
Beta testers who report a bug or send useful feedback get a free 1.0 license. We reply within 24 hours.
What it does
- Real Spaces, synchronized. SpacesSync works with native macOS Spaces. It doesn't replace them, doesn't rearrange your windows, and doesn't require disabling System Integrity Protection.
- Configurable sync groups. Pair the displays you want synchronized; leave the others independent.
- Install and forget. Set it up once, run in the menu bar. No daily interaction, no shortcuts to learn.
- Auto-update built in (via Sparkle). New macOS support arrives in point releases without any reinstall.
- No telemetry. No account. Email is only required at purchase, for license delivery.
Why this exists
Every Space switch on a multi-monitor Mac leaves half your workspace behind. The screen you're not switching from stays on whatever it was — mid-thought, mid-debug, mid-project. What used to be one workspace is now several, and you spend the rest of the day shoving windows back together.
Multi-monitor Spaces broke in 2013, when OS X Mavericks (10.9) shipped “Displays have separate Spaces” turned on by default. Before then, a Space spanned every connected display. Switch on one monitor, and all of them moved.[1] Apple hasn't fixed it in over a decade. We did, without disabling System Integrity Protection and without changing how you use your Mac.
Some users preferred the new per-display behavior. This is for the rest of us: the people who keep one task spread across two screens and want them to move together.
The alternatives (yabai, AeroSpace, dotfiles workarounds) require disabling System Integrity Protection or replacing native Spaces with a tiling window manager. If what you actually want is tiling, those are better fits. SpacesSync is the small, focused, paid utility for people who like native Spaces and just want them synced.
Example setups
A sync group is a set of monitors that switch Spaces together. You pick which monitors go in which group. Any monitor not in a group stays standalone. Its Spaces switch on their own. You can have as many groups as you want.
All monitors synced, any count
- Space 1: Project 1
- Space 2: Project 2
- Space 3: Project 3
Switch on any monitor; they all follow. Add or remove a monitor, and the sync group keeps working.
Three monitors, one standalone + one sync group
- Space A: Messages, FaceTime
- Space B: Spotify
- Space 1: Project 1
- Space 2: Project 2
- Space 3: Project 3
Switch on the middle monitor and the right follows. Left stays put: your music keeps playing, your call stays visible.
Four monitors, two sync groups
- Space 1: Coding
- Space 2: Writing
- Space A: Reference
- Space B: Communications
Each group switches independently. Move group A through Coding and Writing without touching what group B is showing.
You've felt this if…
Two or more monitors. You've noticed Spaces is broken across displays, and you want it fixed without rebuilding how you use your Mac.
- You remember when switching Space on one monitor switched all of them. You want that back.
- You keep a debugger on one screen and the runtime on another. Every Space switch breaks the pairing.
- You work across two screens at once (research + source, code + runtime), and switching Space should bring back the whole pairing, not just one side.
- An interruption hits (a Slack ping, a phone call, an urgent ask), and you need a fresh Space across both monitors to handle it cleanly, then swipe back to where you were.
Status & availability
SpacesSync is in private beta as of June 2026. The 1.0 release is paid: $12.99 USD, perpetual license, three Mac activations per license, and a 14-day refund window through Lemon Squeezy if it isn't a fit.
Tested on macOS 15 Sequoia. Tahoe (macOS 26) is in active testing. We're prioritizing Tahoe support and expect 1.0.1 within a couple of weeks of Tahoe GA. Sparkle auto-update delivers it.
Beta builds are direct-download by request. Beta retires roughly six weeks after 1.0 ships so beta users move to the released build cleanly. Beta testers who report a bug or send useful feedback get a free 1.0 license. That's our thank-you for helping ship it.
Distribution at 1.0:
- Direct purchase via Lemon Squeezy. Perpetual license, 3-Mac activation, 14-day refund window.
- Setapp: in review for inclusion in the Setapp bundle. Setapp subscribers will be able to install at no additional cost once approved.
- Not on the Mac App Store. The work SpacesSync does requires private WindowServer APIs that the App Store review won't pass.
Common questions
- How does the refund work?
- 14 days, no questions. Full refund through Lemon Squeezy. The link is in your purchase email; you don't need to write to anyone.
- When will SpacesSync run on macOS 26 Tahoe?
- Auto-update handles it. You do nothing. Tahoe support ships in 1.0.1; your existing install picks it up via Sparkle.
- Can I see it running before I buy?
- Beta is invite-only right now and a public demo loop ships with 1.0. In the meantime, request a beta invite (above) or email and we'll send you a short Loom recording.
- Can I move my license to a new Mac?
- Yes. Each license covers 3 Mac activations. Deactivate one Mac from the menubar app and activate another whenever you want.
- What happens to my install if Tool Glue Labs disappears?
- License validation is fully offline after first activation. Your installed copy keeps working regardless of network, server, or business status. No phone-home, no kill switch.
- Family pack or team license?
- Not at launch. A single license covers 3 Macs, which fits most households. If you need more, email and we'll figure something out.
- Does it work with a closed laptop lid (clamshell mode)?
- Yes. SpacesSync follows whatever displays macOS reports. Close the lid with an external monitor connected and one display drops out of the sync group cleanly. Reopen and it rejoins.