Built for Airbnb hosts

One code.
Every door.

AirMultiLocks copies guest codes from your primary Airbnb lock to every other smart lock at your property — automatically, on a regular schedule.

Works with Airbnb guest codes Syncs automatically Multiple entry doors Removes expired codes
Get Assisted Setup — $299 Buy DIY Kit — $79.99
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The Problem

Airbnb only solves part of the lock problem.

Airbnb's smart lock integration manages codes on a primary lock — usually the front door. But many rentals have more than one guest-accessible entrance.

Manually copying codes wastes timeOpen three lock apps, type the same code three times, hope you didn't make a typo.
Missed codes create check-in problemsA guest arrives at the side door at 11pm. Their code doesn't work. You get the call.
Expired codes linger on secondary locksOld guest access stays open on doors Airbnb doesn't manage — easy to forget, hard to audit.
More locks = more chances for mistakesGarage, side door, pool gate, basement — each extra door multiplies manual effort.
Without AirMultiLocks
Front Door 4821
→
Airbnb sets this ✓
Your other doors — on their own
Side Door
stale: 3901
Garage Entry
no code
Back Door
forgotten
Every new reservation = copy codes manually to every app. Easy to miss. Easy to forget.
How It Works

AirMultiLocks keeps your locks in sync.

It watches codes on your primary lock and copies them to every selected secondary lock. Code added, changed, or removed — AirMultiLocks handles the rest.

Front Door
Airbnb Primary
AirMultiLocks
Every 15 min
Side Door
Synced ✓
Garage
Synced ✓
Back Door
Synced ✓
Reads codes automatically
Pulls the current code list from your Airbnb-connected primary lock via Seam.
Creates matching codes
Writes the same guest codes to secondary locks with a SYNC: prefix — so AirMultiLocks knows what it owns.
Updates changed codes
When a code changes on the primary lock, all secondary locks are updated at the next sync.
Removes expired codes
When a code disappears from the primary lock, it's removed from all secondary locks too.
Dashboard with full status
Lock status, last sync time, next sync countdown, and a manual Sync Now button.
Adjustable sync interval
Change sync frequency, pause syncing, or trigger an immediate sync anytime.
Important: AirMultiLocks only manages codes it created. Any codes you've added manually to secondary locks are never touched.
Benefits

Less lock admin. Fewer guest problems.

01
Save time
Stop entering the same code into multiple lock apps after every reservation. Set it up once.
02
Reduce check-in issues
Guests use one code across every entry point. No confusion, no late-night access calls.
03
Reliable turnovers
New reservations and changed codes propagate automatically before you think of it.
04
Clean up expired access
Synced codes disappear from secondary locks the moment they leave the primary. No stragglers.
05
Multi-entry properties
Garage, side door, guest suite, pool gate, back entrance — every door covered automatically.
06
You stay in control
Choose your locks, set the sync interval, pause or adjust anytime from the dashboard.
Security

Built with practical host security in mind.

Designed to sync only the codes it manages. Your manual codes stay separate, and the dashboard is protected behind your own admin password.

Password-protected dashboard — admin password stored as a bcrypt hash
Session cookies signed with a generated session secret
Seam API key validated at setup — never exposed via the status API
Config file written with owner-only file permissions
If the primary lock can't be read safely, syncing is skipped to prevent accidental deletions
Offline secondary locks are skipped — never block the rest of the sync
Synced codes prefixed SYNC: — never confused with manual codes
Manual codes on secondary locks are never touched
Dashboard access behind your admin password
Railway URL and API key stay private to you
Keep private: Your Railway URL, admin password, and Seam API key. Treat them like passwords for your lock system.
Setup

Set it up once, then let it run.

About 20–30 minutes the first time. Then it runs on its own, forever.

1
Connect your smart lock to Airbnb
Link your primary door lock to Airbnb so guest codes are managed automatically for each reservation.
2
Connect your locks to Seam
Create a free Seam account and connect your smart locks. Seam supports most major lock brands.
3
Deploy on Railway
One-click deploy keeps AirMultiLocks running 24/7 in the cloud — your computer stays off.
4
Choose your primary lock
Select the Airbnb-connected front door — the lock Airbnb already manages codes on.
5
Select secondary locks
Pick every other door to sync: side, garage, back, pool gate — as many as your Seam plan supports.
6
Create your admin password
Secure your dashboard. Monitor syncs, adjust intervals, or run a manual sync from here.
7
Done — it syncs automatically
AirMultiLocks checks your primary lock regularly and keeps everything matched.
Railway keeps AirMultiLocks running online, so your computer does not need to stay on.
Pricing

Choose the setup that fits you.

DIY Setup Kit
$79.99
Best for hands-on hosts comfortable following a detailed guide.
What's included
  • Self-service AirMultiLocks setup guide
  • Railway deployment walkthrough
  • Seam connection instructions
  • Lock selection guide
  • Troubleshooting checklist
  • Security & maintenance guidance
Buy DIY Kit
Recommended for busy hosts
Assisted Setup
$299
Best for hosts who want it handled correctly without dealing with setup screens.
What's included
  • Fully configured AirMultiLocks deployment
  • Help connecting Seam, Railway, and your locks
  • Primary and secondary lock selection
  • Sync interval configuration
  • Dashboard walkthrough
  • Live support during setup
Get Assisted Setup
"Your guests should not care
which door they use."
One guest code experience
Less manual work between bookings
Fewer late-night access calls
Works for properties with multiple doors
Make every guest code work everywhere it should.
Get Assisted Setup — $299 Buy DIY Kit — $79.99
Questions

Frequently asked.

Yes. AirMultiLocks is designed specifically to work with codes that Airbnb creates on your primary smart lock. When Airbnb adds, changes, or removes a guest code, AirMultiLocks copies that change to your other locks automatically.
Yes. Seam is how AirMultiLocks communicates with your smart locks. It supports most major lock brands. Seam's free tier supports 3 devices per workspace — that's 1 primary lock plus 2 secondary locks. More locks may require a paid Seam plan.
Yes. Railway is where AirMultiLocks runs online, so your computer doesn't need to stay on 24/7. Railway has a free tier that works for most hosts. Setup takes only a few minutes.
No. AirMultiLocks only manages codes it created — tagged with a SYNC: prefix. Any codes you added manually to secondary locks are completely ignored and never touched.
If a secondary lock is offline during a sync, it's skipped and the rest continues normally. The skipped lock will be updated on the next successful sync.
Yes. Syncing runs on a regular schedule, and you can adjust the interval from the dashboard. You can also pause syncing, or trigger an immediate manual sync whenever you need it.
Seam's free tier supports 3 devices total — 1 primary plus 2 secondary locks. For more, a paid Seam plan supports additional devices. AirMultiLocks itself has no built-in limit.
If you're comfortable with web services and following technical guides, the DIY Kit has everything you need. If you'd rather skip the back-and-forth and have it set up correctly — the Assisted Setup is the better investment, especially if a single failed check-in could cost you a five-star review.

Ready to stop copying
lock codes by hand?

AirMultiLocks gives short-term rental hosts a simple way to keep every guest-accessible smart lock aligned with the primary lock Airbnb already manages.

Get Assisted Setup — $299 Buy DIY Kit — $79.99