Master key systems, designed and proved.
Create your keys, tick which doors each one opens, and get a progression chart that has been simulated key-by-cylinder before you see it. Then, when a key goes missing, replace just that key — not the system.
No sign-up for the designer. The app keeps your projects.
The design job, done the way the trade actually works
Tick the keys on each door
Create the keys that open more than one door — a floor master, a cleaner’s key — then tick which ones open each door. Own keys, keyed-alike doors, cross-keyed doors and maisons all come from the ticks. Who sits under whom is worked out for you.
Proved, not promised
Every system is simulated key-by-cylinder at the shear line before it is shown. Every key opens exactly its doors and nothing else, every master pin is even and 2–8, no chamber carries more than three, MACS 7 holds everywhere. If no clean system exists, it says so.
Replace one key, not the system
A tenant loses their keys. Re-pin only the cylinders that key operated onto a ghost bitting the progression never issued. Every other key keeps working. You get the new cuts, the pin changes per cylinder, and the easy change key. How it works →
Design here. Keep it in the app.
The designer on this site runs entirely in your browser and stores nothing — a system lives in the page and, if you copy the link, in the URL. The app is where projects persist, get revised and get cut.
| Designer (this site) | The app | |
|---|---|---|
| Sign-up | None | Free account |
| Keys ticked per door, hierarchy inferred | Yes | Doors, keys and a GGMK → GMK → MK → CK hierarchy you lay out |
| Cross-keyed and maison doors proved at the shear line | Yes | Next in line for the same rules — design those here for now |
| Size | 16 doors, 8 shared keys plus an own key per door, 3 levels under the top key | No door limit |
| Saving and revising later | No — share by link | Projects persist and can be re-generated and edited |
| Cutting register (cut counts, next stamp number) | No | Yes |
| Replace this key (ghost-key replacement) | Yes — with a retired-bitting list in the link | Next in line for saved projects |
Free to design. A few dollars to design without limits.
Designer
- No account, nothing stored
- Up to 16 doors and 8 shared keys
- Proof matrix, pin stacks, share by link
- Replace this key
App — Free
- Saved projects, revise any time
- One brand-new system each calendar month
- Unlimited editing and re-generation of existing systems
- Cutting register
App — Pro
- Unlimited new systems
- Everything in Free
- Billed through the App Store and Google Play
- Subscriptions opening soon — no card details taken on the web
Built in a working locksmith business
Masterkeying comes out of Access Locksmiths in Brisbane, where master key systems are designed, pinned and cut every week. The rules in the engine are the ones used on the bench — not a textbook’s. The free designer also runs on their site. The app and this site are built on Launchr.
Questions, a system that stumped the engine, a keyway it should know about: hello@masterkeying.app.